WorldWideScience

Sample records for reaction chamber wall

  1. Liquid Wall Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  2. Sleeve reaction chamber system

    Science.gov (United States)

    Northrup, M Allen [Berkeley, CA; Beeman, Barton V [San Mateo, CA; Benett, William J [Livermore, CA; Hadley, Dean R [Manteca, CA; Landre, Phoebe [Livermore, CA; Lehew, Stacy L [Livermore, CA; Krulevitch, Peter A [Pleasanton, CA

    2009-08-25

    A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

  3. Pressurized air ionization chamber with aluminium walls for radiometric dosimetry

    International Nuclear Information System (INIS)

    Rodrigues, R.G.S.; Pela, C.A.; Netto, T.G.

    1996-01-01

    A pressurized air ionization chamber with 23 cm 3 and aluminium walls is evaluated concerning its sensitiveness in low exposure rate. Considering conventional ionization chambers, this chamber shows a better performance since the air pressure of 2500 kPa minimizes the energy dependence to less than 5% between 40 and 1.250 keV

  4. Very high intensity reaction chamber design

    International Nuclear Information System (INIS)

    Devaney, J.J.

    1975-09-01

    The problem of achieving very high intensity irradiation by light in minimal regions was studied. Three types of irradiation chamber are suggested: the common laser-reaction chamber, the folded concentric or near-concentric resonator, and the asymmetric confocal resonator. In all designs the ratio of high-intensity illuminated volume to other volume is highly dependent (to the 3 / 2 power) on the power and fluence tolerances of optical elements, primarily mirrors. Optimization of energy coupling is discussed for the common cavity. For the concentric cavities, optimization for both coherent and incoherent beams is treated. Formulae and numerical examples give the size of chambers, aspect ratios, maximum pass number, image sizes, fluences, and the like. Similarly for the asymmetric confocal chamber, formulae and numerical examples for fluences, dimensions, losses, and totally contained pass numbers are given

  5. Effect of Chamber Wall Proximity on Radiometer Force Production (Preprint)

    National Research Council Canada - National Science Library

    Selden, N. P; Gimelshein, N. E; Gimelshein, S. F; Ketsdever, A. D

    2008-01-01

    ... on a given radiometer configuration in both the free molecule and transitional regimes. The contribution of the chamber walls to both the flowfield structure and radiometric force production were examined for helium, argon, and nitrogen test gases...

  6. Influence of reaction chamber shape on cast-iron spheroidization process in-mold

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2010-01-01

    Full Text Available This paper presents a results concerning the influence of reaction chamber shape on cast – iron spheroidization process in form. The volume of the tested reaction chambers was about 118000mm3. Reaction chambers in the shape of: rectangular, cylinder and spherical cap were examined. It has been shown that the best graphite spheroidizing process was provided by spherical cap chamber shape. The reaction of cast – iron with magnesium in reaction chamber depends on the flow of cast – iron in the chamber. In rectangular and cylinder shape chambers proceed the impact of diphase stream on flat bottom wall. It causes the creation on its surface film, called: cast – iron “film”, where single grains of magnesium master alloy exist. The largest part of master alloy is drifted by liquid cast – iron to the top and only there graphite spheroidization process proceed. In the spherical cap shape reaction chamber, as a result of rotation movement of liquid cast – iron throughout its volume, graphite spheroidization process proceed. Apart from the reaction chamber shape, applying of mixing chamber ensure full cast – iron spheroidization process.

  7. Progress towards realization of a laser IFE solid wall chamber

    International Nuclear Information System (INIS)

    Raffray, A.R.; Blanchard, J.; Latkowski, J.; Najmabadi, F.; Renk, T.; Sethian, J.; Sharafat, S.; Snead, L.

    2006-01-01

    The high average power laser (HAPL) program aims at developing laser inertial fusion energy (Laser IFE) based on lasers, direct drive targets and a solid wall chamber. The preferred first wall configuration is based on tungsten and ferritic steel as armor and structural materials, respectively. A key concern is the survival of the first wall under the X-ray and ion energy deposition from the fusion micro-explosion. The HAPL design and R and D effort in the chamber and material area is focused toward understanding and resolving the key armor survival issues. This includes modeling and experimental testing of the armor thermo-mechanical behavior in facilities utilizing ion, X-rays and laser sources to simulate IFE conditions. Helium management is addressed by conducting implantation experiments along with modeling of He behavior in tungsten. This paper summarizes the HAPL chamber activities. The first wall/armor configuration and design analysis are described, key chamber issues are discussed, and the R and D to address them is highlighted

  8. Lean premixed reacting flows with swirl and wall-separation zones in a contracting chamber

    Science.gov (United States)

    Zhang, Yuxin; Rusak, Zvi; Wang, Shixiao

    2017-11-01

    Low Mach number lean premixed reacting swirling flows with wall-separation zones in a contracting circular finite-length open chamber are studied. Assuming a complete reaction with high activation energy and chemical equilibrium behind the reaction zone, a nonlinear partial differential equation is derived for the solution of the flow stream function behind the reaction zone in terms of the inlet total enthalpy for a reacting flow, specific entropy and the circulation functions. Bifurcation diagrams of steady flows are described as the inlet swirl level is increased at fixed chamber contraction and reaction heat release. The approach is applied to an inlet solid-body rotation flow with constant profiles of the axial velocity, temperature and mixture reactant mass fraction. The computed results provide predictions of the critical inlet swirl levels for the first appearance of wall-separation states and for the size of the separation zone as a function of the inlet swirl ratio, Mach number, chamber contraction and heat release of the reaction. The methodology developed in this paper provides a theoretical feasibility for the development of the technology of swirl-assisted combustion where the reaction zone is supported and stabilized by a wall-separation zone.

  9. Operational Windows for Dry-Wall and Wetted-Wall IFE Chambers

    International Nuclear Information System (INIS)

    Najmabadi, F.; Raffray, A.R.; Bromberg, L.

    2004-01-01

    The ARIES-IFE study was an integrated study of inertial fusion energy (IFE) chambers and chamber interfaces with the driver and target systems. Detailed analysis of various subsystems was performed parametrically to uncover key physics/technology uncertainties and to identify constraints imposed by each subsystem. In this paper, these constraints (e.g., target injection and tracking, thermal response of the first wall, and driver propagation and focusing) were combined to understand the trade-offs, to develop operational windows for chamber concepts, and to identify high-leverage research and development directions for IFE research. Some conclusions drawn in this paper are (a) the detailed characterization of the target yield and spectrum has a major impact on the chamber; (b) it is prudent to use a thin armor instead of a monolithic first wall for dry-wall concepts; (c) for dry-wall concepts with direct-drive targets, the most stringent constraint is imposed by target survival during the injection process; (d) for relatively low yield targets (<250 MJ), an operational window with no buffer gas may exist; (e) for dry-wall concepts with indirect-drive targets, a high buffer gas pressure would be necessary that may preclude propagation of the laser driver and require assisted pinch transport for the heavy-ion driver; and (f) generation and transport of aerosols in the chamber is the key feasibility issue for wetted-wall concepts

  10. Photocatalytic surface reactions on indoor wall paint.

    Science.gov (United States)

    Salthammer, T; Fuhrmann, F

    2007-09-15

    The reduction of indoor air pollutants by air cleaning systems has received considerable interest, and a number of techniques are now available. So far, the method of photocatalysis was mainly applied by use of titanium dioxide (TiO2) in flow reactors under UV light of high intensity. Nowadays, indoor wall paints are equipped with modified TiO2 to work as a catalyst under indoor daylight or artificial light. In chamber experiments carried out under indoor related conditions itwas shown thatthe method works for nitrogen dioxide with air exchange and for formaldehyde without air exchange at high concentrations. In further experiments with volatile organic compounds (VOCs), a small effect was found for terpenoids with high kOH rate constants. For other VOCs and carbon monoxide there was no degradation at all or the surface acted as a reversible sink. Secondary emissions from the reaction of paint constituents were observed on exposure to light. From the results it is concluded that recipes of photocatalytic wall paints need to be optimized for better efficiency under indoor conditions.

  11. Pressure vessel rupture within a chamber: the pressure history on the chamber wall

    International Nuclear Information System (INIS)

    Baum, M.R.

    1989-04-01

    Generally there is a large number of pressure vessels containing high pressure gas on power stations and chemical plant. In many instances, particularly on power plant, these vessels are within the main building. If a pressure vessel were to fail, the surrounding structures would be exposed to blast loads and the forces resulting from jets of fluid issuing from the breached vessel. In the case where the vessel is in a relatively closed chamber there would also be a general overpressurisation of the chamber. At the design stage it is therefore essential to demonstrate that the plant could be safely shut down in the event of a pressure vessel failure, that is, it must be shown that the chamber will not collapse thus putting the building at risk or hazarding equipment essential for a safe shut down. Such an assessment requires the loads applied to the chamber walls, roof, etc. to be known. (author)

  12. Potential design modifications for the High Yield Lithium Injection Fusion Energy (HYLIFE) reaction chamber

    International Nuclear Information System (INIS)

    Pitts, J.H.; Hovingh, J.; Meier, W.R.; Monsler, M.J.; Powell, E.G.; Walker, P.E.

    1979-01-01

    Generation of electric power from inertial confinement fusion requires a reaction chamber. One promising type, the High Yield Lithium Injection Fusion Energy (HYLIFE) chamber, includes a falling array of liquid lithium jets. These jets act as: (1) a renewable first wall and blanket to shield metal components from x-ray and neutron exposure, (2) a tritium breeder to replace tritium burned during the fusion process, and (3) an absorber and transfer medium for fusion energy. Over 90% of the energy produced in the reaction chamber is absorbed in the lithium jet fall. Design aspects are included

  13. Plasma Chamber and First Wall of the Ignitor Experiment^*

    Science.gov (United States)

    Cucchiaro, A.; Coppi, B.; Bianchi, A.; Lucca, F.

    2005-10-01

    The new designs of the Plasma Chamber (PC) and of the First Wall (FW) system are based on updated scenarios for vertical plasma disruption (VDE) as well as estimates for the maximum thermal wall loadings at ignition. The PC wall thickness has been optimized to reduce the deformation during the worst disruption event without sacrificing the dimensions of the plasma column. A non linear dynamic analysis of the PC has been performed on a 360^o model of it, taking into account possible toroidal asymmetries of the halo current. Radial EM loads obtained by scaling JET measurements have been also considered. The low-cycle fatigue analysis confirms that the PC is able to meet a lifetime of few thousand cycles for the most extreme combinations of magnetic fields and plasma currents. The FW, made of Molybdenum (TZM) tiles covering the entire inner surface of the PC, has been designed to withstand thermal and EM loads, both under normal operating conditions and in case of disruption. Detailed elasto-plastic structural analyses of the most (EM) loaded tile-carriers show that these are compatible with the adopted fabrication requirements. ^*Sponsored in part by ENEA of Italy and by the U.S. DOE.

  14. High vacuum general purpose scattering chamber for nuclear reaction study

    International Nuclear Information System (INIS)

    Suresh Kumar; Ojha, S.C.

    2003-01-01

    To study the nuclear reactions induced by beam from medium energy accelerators, one of the most common facility required is a scattering chamber. In the scattering chamber, projectile collides with the target nucleus and the scattered reaction products are detected with various type of nuclear detector at different angles with respect to the beam. The experiments are performed under high vacuum to minimize the background reaction and the energy losses of the charged particles. To make the chamber general purpose various requirement of the experiments are incorporated into it. Changing of targets, changing angle of various detectors while in vacuum are the most desired features. The other features like ascertaining the beam spot size and position on the target, minimizing the background counts by proper beam dump, accurate positioning of the detector as per plan etc. are some of the important requirements

  15. Inertial confinement fusion reaction chamber and power conversion system study

    International Nuclear Information System (INIS)

    Maya, I.; Schultz, K.R.; Battaglia, J.M.

    1984-09-01

    GA Technologies has developed a conceptual ICF reactor system based on the Cascade rotating-bed reaction chamber concept. Unique features of the system design include the use of low activation SiC in a reaction chamber constructed of box-shaped tiles held together in compression by prestressing tendons to the vacuum chamber. Circulating Li 2 O granules serve as the tritium breeding and energy transport material, cascading down the sides of the reaction chamber to the power conversion system. The total tritium inventory of the system is 6 kg; tritium recovery is accomplished directly from the granules via the vacuum system. A system for centrifugal throw transport of the hot Li 2 O granules from the reaction chamber to the power conversion system has been developed. A number of issues were evaluated during the course of this study. These include the response of first-layer granules to the intense microexplosion surface heat flux, cost effective fabrication of Li 2 O granules, tritium inventory and recovery issues, the thermodynamics of solids-flow options, vacuum versus helium-medium heat transfer, and the tradeoffs of capital cost versus efficiency for alternate heat exchange and power conversion system option. The resultant design options appear to be economically competitive, safe, and environmentally attractive

  16. First-wall-coating candidates for ICF reactor chambers using dry-wall protection only

    International Nuclear Information System (INIS)

    Sink, D.A.

    1983-01-01

    Twenty pure metals were considered as potential candidates for first-wall coatings of ICF reactor chambers. Seven were found to merit further consideration based on the results of computer-code calculations of figures-of-merit. The seven are rhenium, iridium, molybdenum, chromium, tungsten, tantalum, and niobium (listed in order of decreasing values of figures-of-merit). The calculations are based on mechanical, thermal, and vacuum vaporization engineering constraints. A number of alloys of these seven metals are suggested as additional candidates

  17. Nuclear targets, recoil ion catchers and reaction chambers

    NARCIS (Netherlands)

    Dionisio, JS; Vieu, C; Schuck, C; Collatz, R; Meunier, R; Ledu, D; Folger, H; Lafoux, A; Lagrange, JM; Pautrat, M; Waast, B; Phillips, WR; Blunt, D; Durell, JL; Varley, BJ; Dagnall, PG; Dorning, SJ; JONES, MA; Smith, AG; Bacelar, JCS; Rzaca-Urban, T; Amzal, N; Meliani, Z; Vanhorenbeeck, J; Passoja, A; Urban, W

    1998-01-01

    The main features of nuclear targets, recoil ion catchers and reaction chambers used in nuclear spectroscopic investigations involving in-beam multi-e-gamma spectrometers are discussed. The relative importance of the F-ray background due to the accelerated ion-target and the recoil-ion-target

  18. Chamber wall response to target implosion in inertial fusion reactors : new and critical assessments

    International Nuclear Information System (INIS)

    Hassanein, A.; Morozov, V.

    2002-01-01

    The chamber walls in inertial fusion energy (IFE) reactors are exposed to harsh conditions following each target implosion. Key issues of the cyclic IFE operation include intense photon and ion deposition, wall thermal and hydrodynamic evolution, wall erosion and fatigue lifetime, and chamber clearing and evacuation to ensure desirable conditions prior to target implosion. Several methods for wall protection have been proposed in the past, each having its own advantages and disadvantages. These methods include use of solid bare walls, gas-filled cavities, and liquid walls/jets. Detailed models have been developed for reflected laser light, emitted photons, and target debris deposition and interaction with chamber components and have been implemented in the comprehensive HEIGHTS software package. The hydrodynamic response of gas filled cavities and photon radiation transport of the deposited energy has been calculated by means of new and advanced numerical techniques. Fragmentation models of liquid jets as a result of the deposited energy have also been developed, and the impact on chamber clearing dynamics has been evaluated. Th focus of this study is to critically assess the reliability and the dynamic response of chamber walls in various proposed protection methods for IFE systems. Of particular concern is the effect on wall erosion lifetime of various erosion mechanisms, such as vaporization, chemical and physical sputtering, melt/liquid splashing and explosive erosion, and fragmentation of liquid walls

  19. Plasma interactions with the outboard chamber wall in DIII-D

    International Nuclear Information System (INIS)

    Rudakov, D.L.; Boedo, J.A.; Yu, J.H.; Brooks, N.H.; Fenstermacher, M.E.; Groth, M.; Hollmann, E.M.; Lasnier, C.J.; McLean, A.G.; Moyer, R.A.; Stangeby, P.C.; Tynan, G.R.; Wampler, W.R.; Watkins, J.G.; West, W.P.; Wong, C.P.C.; Bastasz, R.J.; Buchenauer, D.; Whaley, J.

    2009-01-01

    Erosion of the main chamber plasma-facing components is of concern for ITER. Plasma interaction with the outboard chamber wall is studied in DIII-D using Langmuir probes and optical diagnostics. Fast camera data shows that edge localized modes (ELMs) feature helical filamentary structures propagating towards the outboard wall. Upon reaching the wall, filaments result in regions of local intense plasma-material interaction (PMI) where peak incident particle and heat fluxes are up to two orders of magnitude higher than those between ELMs. In low density/collisionality H-mode discharges, PMI at the outboard wall is almost entirely due to ELMs. A moderate change of the gap between the separatrix and the outer wall strongly affects PMI intensity at the wall. Material samples exposed near the outboard wall showed net carbon deposition in high-density discharges (near the Greenwald limit) and tendency towards net erosion in lower density discharges (∼0.45 of the Greenwald limit).

  20. Chamber wall response to target implosion in inertial fusion reactors: new and critical assessments

    International Nuclear Information System (INIS)

    Hassanein, A.; Morozov, V.

    2002-01-01

    The chamber walls in inertial fusion energy (IFE) reactors are exposed to harsh conditions following each target implosion. Key issues of the cyclic IFE operation include intense photon and ion deposition, wall thermal and hydrodynamic evolution, wall erosion and fatigue lifetime, and chamber clearing and evacuation to ensure desirable conditions prior to next target implosion. Several methods for wall protection have been proposed in the past, each having its own advantages and disadvantages. These methods include use of solid bare walls, gas-filled cavities, and liquid walls/jets. Detailed models have been developed for reflected laser light, emitted photons, and target debris deposition and interaction with chamber components and have been implemented in the comprehensive HEIGHTS software package. The focus of this study is to critically assess the reliability and the dynamic response of chamber walls in IFE systems. Of particular concern is the effect on wall erosion lifetime due to various erosion mechanisms, such as vaporization, chemical and physical sputtering, melt/liquid splashing and explosive erosion, and fragmentation of liquid walls

  1. Method and apparatus for active control of combustion rate through modulation of heat transfer from the combustion chamber wall

    Science.gov (United States)

    Roberts, Jr., Charles E.; Chadwell, Christopher J.

    2004-09-21

    The flame propagation rate resulting from a combustion event in the combustion chamber of an internal combustion engine is controlled by modulation of the heat transfer from the combustion flame to the combustion chamber walls. In one embodiment, heat transfer from the combustion flame to the combustion chamber walls is mechanically modulated by a movable member that is inserted into, or withdrawn from, the combustion chamber thereby changing the shape of the combustion chamber and the combustion chamber wall surface area. In another embodiment, heat transfer from the combustion flame to the combustion chamber walls is modulated by cooling the surface of a portion of the combustion chamber wall that is in close proximity to the area of the combustion chamber where flame speed control is desired.

  2. An open-walled ionization chamber appropriate to tritium monitoring for glovebox

    International Nuclear Information System (INIS)

    Chen Zhilin; Chang Ruiming; Mu Long; Song Guoyang; Wang Heyi; Wu Guanyin; Wei Xiye

    2010-01-01

    An open-walled ionization chamber is developed to monitor the tritium concentration in gloveboxes in tritium processing systems. Two open walls are used to replace the sealed wall in common ionization chambers, through which the tritium gas can diffuse into the chamber without the aid of pumps and pipelines. Some basic properties of the chamber are examined to evaluate its performance. Results turn out that an open-walled chamber of 1 l in volume shows a considerably flat plateau over 700 V for a range of tritium concentration. The chamber also gives a good linear response to gamma fields over 4 decades under a pressure condition of 1 atm. The pressure dependence characteristics show that the ionization current is only sensitive at low pressures. The pressure influence becomes weaker as the pressure increases mainly due to the decrease in the mean free path of β particles produced by tritium decay. The minimum detection limit of the chamber is 3.7x10 5 Bq/m 3 .

  3. Wall attenuation and scatter corrections for ion chambers: measurements versus calculations

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, D W.O.; Bielajew, A F [National Research Council of Canada, Ottawa, ON (Canada). Div. of Physics

    1990-08-01

    In precision ion chamber dosimetry in air, wall attenuation and scatter are corrected for A{sub wall} (K{sub att} in IAEA terminology, K{sub w}{sup -1} in standards laboratory terminology). Using the EGS4 system the authors show that Monte Carlo calculated A{sub wall} factors predict relative variations in detector response with wall thickness which agree with all available experimental data within a statistical uncertainty of less than 0.1%. They calculated correction factors for use in exposure and air kerma standards are different by up to 1% from those obtained by extrapolating these same measurements. Using calculated correction factors would imply increases of 0.7-1.0% in the exposure and air kerma standards based on spherical and large diameter, large length cylindrical chambers and decreases of 0.3-0.5% for standards based on large diameter pancake chambers. (author).

  4. Identification of the heart wall and chamber based on temporal change of ultrasonic scatterer distribution

    Science.gov (United States)

    Takahashi, Kohei; Taki, Hirofumi; Kanai, Hiroshi

    2017-07-01

    In most current methods for evaluating the cardiac function by ultrasound, the heart wall area is identified manually by an examiner. To eliminate examiner dependence and to improve usability, an automatic heart wall identification method is desirable. Identification based on only echogenicity often fails because of low echogenicity of some areas of the heart wall. In the present study, to determine more essential features, we focused on the relative temporal change of ultrasonic scatterer distribution and proposed three features for identification of the heart wall and the chamber: cross-correlation of RF signals, that of envelopes, and spatial dispersion of movement vectors in small regions. In an in vivo experiment, using echogenicity and the three features, we identified the heart wall and the chamber in the left ventricular long-axis view, resulting in criteria of separability J of 1.69, 1.40, and 3.02 using these features compared with the result of 0.979 using echogenicity.

  5. A plant chamber system with downstream reaction chamber to study the effects of pollution on biogenic emissions

    NARCIS (Netherlands)

    Timovsky, J.; Gankema, Paulien; Pierik, Ronald; Holzinger, Rupert

    2014-01-01

    A system of two plant chambers and a downstream reaction chamber has been set up to investigate the emission of biogenic volatile organic compounds (BVOCs) and possible effects of pollutants such as ozone. The system can be used to compare BVOC emissions from two sets of differently treated plants,

  6. Special design issues. Ion beam driver-reaction chamber interfaces

    International Nuclear Information System (INIS)

    Moir, R.W.; Peterson, R.R.; Kessler, G.

    1995-01-01

    Design issues of the interface between ion beam drivers and the reaction chamber for heavy ion beam and light ion beam inertial fusion drivers are discussed. The interface must provide for radiation protection of final focusing magnets, pumping of evaporated material and non-condensable gas that enter the beam ports, thermal insulation, heat removal, a.o.. Beam ports and focal magnets must be protected by neutronically thick shielding between the beam path and the magnet conductor. The required thickness of the shielding determines the minimum spacing between individual beams in a cluster of beams. The cone angle of this cluster can affect target performance. The beamlines are subjected to evaporated material, debris, and rapidly moving droplets. The reaction chambers used here are HYLIFE-II for indirect, HIBALL-II for direct drive. The light ion beam interface is based on the LIBRA and LIBRA-LiTE studies. In the case of HYLIFE-II, liquid jets must be demonstrated with a thickness of 0.5 m and with an edge that comes to within 10 mm of the beam edges to protect the ports. Design of compact focal arrays with enough shielding to give magnets an adequate lifetime must be achieved. As shielding is added the size of the beam array will grow and the target will drop. For HIBALL neutron shielding of the focal magnets provides an adequate lifetime. Replaceable special INPORT units will have to be developed in the region of the beam ports. For light ions transport issues have led to structures being placed close enough to the target that they experience a higher neutron damage rate and must be replaced once or twice a year, which would require remote maintenance. Light ion concepts could greatly benefit from a self-pinched transport scheme, though the details are unclear and the effect on availability is uncertain. Light and heavy ions have similar problems in keeping the gas in the drivers at a low density. Both will require active means to preserve this low density, while

  7. Inertial confinement fusion reaction chamber and power conversion system study. Final report

    International Nuclear Information System (INIS)

    Maya, I.; Schultz, K.R.; Bourque, R.F.

    1985-10-01

    This report summarizes the results of the second year of a two-year study on the design and evaluation of the Cascade concept as a commercial inertial confinement fusion (ICF) reactor. We developed a reactor design based on the Cascade reaction chamber concept that would be competitive in terms of both capital and operating costs, safe and environmentally acceptable in terms of hazard to the public, occupational exposure and radioactive waste production, and highly efficient. The Cascade reaction chamber is a double-cone-shaped rotating drum. The granulated solid blanket materials inside the rotating chamber are held against the walls by centrifugal force. The fusion energy is captured in a blanket of solid carbon, BeO, and LiAlO 2 granules. These granules are circulated to the primary side of a ceramic heat exchanger. Primary-side granule temperatures range from 1285 K at the LiAlO 2 granule heat exchanger outlet to 1600 K at the carbon granule heat exchanger inlet. The secondary side consists of a closed-cycle gas turbine power conversion system with helium working fluid, operating at 1300 K peak outlet temperature and achieving a thermal power conversion efficiency of 55%. The net plant efficiency is 49%. The reference design is a plant producing 1500 MW of D-T fusion power and delivering 815 MW of electrical power for sale to the utility grid. 88 refs., 44 figs., 47 tabs

  8. The thin-wall tube drift chamber operating in vacuum (prototype)

    Science.gov (United States)

    Alexeev, G. D.; Glonti, L. N.; Kekelidze, V. D.; Malyshev, V. L.; Piskun, A. A.; Potrbenikov, Yu. K.; Rodionov, V. K.; Samsonov, V. A.; Tokmenin, V. V.; Shkarovskiy, S. N.

    2013-08-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. "Self-centering" spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

  9. The thin-wall tube drift chamber operating in vacuum (prototype)

    International Nuclear Information System (INIS)

    Alexeev, G.D.; Glonti, L.N.; Kekelidze, V.D.; Malyshev, V.L.; Piskun, A.A.; Potrbenikov, Yu.K.; Rodionov, V.K.; Samsonov, V.A.; Tokmenin, V.V.; Shkarovskiy, S.N.

    2013-01-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum

  10. The thin-wall tube drift chamber operating in vacuum (prototype)

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, G.D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Glonti, L.N., E-mail: glonti@sunse.jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kekelidze, V.D.; Malyshev, V.L.; Piskun, A.A.; Potrbenikov, Yu.K.; Rodionov, V.K.; Samsonov, V.A.; Tokmenin, V.V.; Shkarovskiy, S.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2013-08-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

  11. Resistive wall heating due to image current on the beam chamber for a superconducting undulator.

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. H. (Accelerator Systems Division (APS))

    2012-03-27

    The image-current heating on the resistive beam chamber of a superconducting undulator (SCU) was calculated based on the normal and anomalous skin effects. Using the bulk resistivity of copper for the beam chamber, the heat loads were calculated for the residual resistivity ratios (RRRs) of unity at room temperature to 100 K at a cryogenic temperature as the reference. Then, using the resistivity of the specific aluminum alloy 6053-T5, which will be used for the SCU beam chamber, the heat loads were calculated. An electron beam stored in a storage ring induces an image current on the inner conducting wall, mainly within a skin depth, of the beam chamber. The image current, with opposite charge to the electron beam, travels along the chamber wall in the same direction as the electron beam. The average current in the storage ring consists of a number of bunches. When the pattern of the bunched beam is repeated according to the rf frequency, the beam current may be expressed in terms of a Fourier series. The time structure of the image current is assumed to be the same as that of the beam current. For a given resistivity of the chamber inner wall, the application ofthe normal or anomalous skin effect will depend on the harmonic numbers of the Fourier series of the beam current and the temperature of the chamber. For a round beam chamber with a ratius r, much larger than the beam size, one can assume that the image current density as well as the density square, may be uniform around the perimeter 2{pi}r. For the SCU beam chamber, which has a relatively narrow vertical gap compared to the width, the effective perimeter was estimated since the heat load should be proportional to the inverse of the perimeter.

  12. Simulation of pulverized coal fired boiler: reaction chamber

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, C.P.; Lansarin, M.A.; Secchi, A.R.; Mendes, T.F. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica. Grupo de Modelagem, Simulacao, Controle e Otimizacao de Processos)]. E-mail: {cperdomo, marla, arge, talita}@enq.ufrgs.br

    2005-06-15

    This work is part of a joint project to built a computational tool for power plant simulation, dealing specifically with the reaction chamber (place of the boiler where the fuel is burned). In order to describe the conversion of chemical energy to thermal energy, an one dimensional pseudo-homogeneous mathematical model, with variable physical properties, and based on mass and energy balances, was developed. The equations were implemented in the gPROMS simulator and the model parameters were estimated using the module gEST of this software, with experimental data from a large-scale coal-fired utility boiler and kinetic data from the open literature. The results showed that the model predicts the composition of the outlet combustion gas satisfactorily. (author)

  13. The influence of wall resonances on the levitation of objects in a single-axis acoustic processing chamber

    Science.gov (United States)

    Ross, B. B.

    1980-01-01

    Instabilities were observed in high temperature, single axis acoustic processing chambers. At certain temperatures, strong wall resonances were generated within the processing chamber itself and these transverse resonances were thought sufficient to disrupt the levitation well. These wall resonances are apparently not strong enough to cause instabilities in the levitation well.

  14. Interaction of cover and target with xenon gas in the IFE-reaction chamber

    International Nuclear Information System (INIS)

    Kuteev, Boris V.

    2001-11-01

    Interaction of a direct drive target and a cover, which is shielding the target against gas particle and heat flows in the reaction chamber of the Inertial Confinement Reactor, is considered. The cover is produced from solid gas -deuterium, neon of xenon. It is shown that at the SOMBRERO parameters the xenon cover with 5.6-mm size significantly reduces the heat flows onto the 4-mm target. The gas drag produces the deceleration of the target much larger than that for the cover due to large mass difference between them. The distance between the target and the cover is about 15 mm at the explosion point, which is sufficient for normal irradiation of the target by laser beams. Protection of the target against the wall radiation is necessary during the flight. Along with creation of reflecting layers over the target surface ablating layers from solid hydrogen or neon seem to be a solution. (author)

  15. Laser fusion reactor design in a fast ignition with a dry wall chamber

    International Nuclear Information System (INIS)

    Ogawa, Yichi; Goto, Takuya; Ninomiya, Daisuke; Hiwatari, Ryoji; Asaoka, Yoshiyuki; Okano, Kunihiko

    2007-01-01

    One of the critical issues in laser fusion reactor design is high pulse heat load on the first wall by the X-rays and the fast/debris ions from fusion burn. There are mainly two concepts for the first wall of laser fusion reactor, a dry wall and a liquid metal wall. We should notice that the fast ignition method can achieve sufficiently high pellet gain with smaller (about 1/10 of the conventional central ignition method) input energy. To take advantage of this property, the design of a laser fusion reactor with a small size dry wall chamber may become possible. Since a small fusion pulse leads to a small electric power, high repetition of laser irradiation is required to keep sufficient electric power. Then we tried to design a laser fusion reactor with a dry wall chamber and a high repetition laser. This is a new challenging path to realize a laser fusion plant. Based on the point model of the core plasma, we have estimated that fusion energy in one pulse can be reduced to be 40 MJ with a pellet gain around G>100. To evaluate the validity of this simple estimation and to optimize the pellet design and the pulse shaping for the fast ignition scenario, we have introduced 1-D hydrodynamic simulation code ILESTA-1D and carried out implosion simulations. Since the code is one-dimensional, the detailed physics process of fast heating cannot be reproduced. Thus the fast heating is reflected in the code as the additional artificial heating source in the energy equation. It is modeled as a homogeneous heating of electrons in core region at the time just before when the maximum compression is achieved. At present we obtained the pellet gain G∝100 with the same input energy as the above estimation by a simple point model (350kJ for implosion, 50kJ for heating and assuming 20% coupling of heating laser). A dry wall is exposed to several threats due to the cyclic load by the high energy X-ray and charged particles: surface melting, physical and chemical sputtering

  16. Climate Chamber Experiment-Based Thermal Analysis and Design Improvement of Traditional Huizhou Masonry Walls

    Directory of Open Access Journals (Sweden)

    Ling Dong

    2018-03-01

    Full Text Available Supported by thousands of years of history, traditional Huizhou buildings have played a vital role, both functionally and culturally, as residential buildings in China. Masonry walls are one of the key building components of a Huizhou building; however, the traditional Huizhou masonry wall structure, predominantly a hollow brick structure, cannot meet the local building energy code requirements, and thus needs to be improved. Within this context, the present research measures the actual thermal performance of traditional Huizhou masonry walls for historical buildings and new-built buildings, which results in mean thermal transmittances of 1.892 W/m2·K and 2.821 W/m2·K, respectively, while the local building energy code requires a minimum thermal transmittance of 1.500 W/m2·K. In order to improve the thermal performance of traditional Huizhou masonry walls, four design scenarios for wall insulation are proposed and tested in a climate chamber: (1 hollow brick wall with inorganic interior insulation mortar, (2 solid brick wall with inorganic interior insulation mortar, (3 hollow brick wall with foamed concrete, and (4 hollow brick wall with foamed concrete plus inorganic interior insulation mortar. The experiment results indicate that, among the four proposed design scenarios, only scenario 4 can significantly improve the thermal performance of Huizhou masonry walls and meet the building energy code requirements, with a mean thermal transmittance of 1.175 W/m2·K. This research lays the foundation for improving the thermal performance of Huizhou masonry walls with new insulation and construction technology, thereby helping to improve the quality of life of Huizhou residents while respecting the cultural significance of the traditional Huizhou building.

  17. Indication chamber of liquid metal fired steam generators with double wall for heat transfer

    International Nuclear Information System (INIS)

    Matal, O.; Martoch, J.

    1982-01-01

    The double wall of the steam generator consists of inner and outer tubes anchored in a tube plate. Between the tubes are indication spaces which end in recesses formed at least in one of the tube plates and coaxial with the outer tubes. The recesses interconnected with channels form the indication chamber to which is connected at least one sensor of the alarm signal equipment. (B.S.)

  18. Radial force on the vacuum chamber wall during thermal quench in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Pustovitov, V. D., E-mail: pustovitov-vd@nrcki.ru [National Research Centre Kurchatov Institute (Russian Federation)

    2015-12-15

    The radial force balance during a thermal quench in tokamaks is analyzed. As a rule, the duration τ{sub tp} of such events is much shorter than the resistive time τ{sub w} of the vacuum chamber wall. Therefore, the perturbations of the magnetic field B produced by the evolving plasma cannot penetrate the wall, which makes different the magnetic pressures on its inner and outer sides. The goal of this work is the analytical estimation of the resulting integral radial force on the wall. The plasma is considered axially symmetric; for the description of radial forces on the wall, the results of V.D. Shafranov’s classical work [J. Nucl. Energy C 5, 251 (1963)] are used. Developed for tokamaks, the standard equilibrium theory considers three interacting systems: plasma, poloidal field coils, and toroidal field coils. Here, the wall is additionally incorporated with currents driven by ∂B/∂t≠0 accompanying the fast loss of the plasma thermal energy. It is shown that they essentially affect the force redistribution, thereby leading to large loads on the wall. The estimates prove that these loads have to be accounted for in the disruptive scenarios in large tokamaks.

  19. Mutagenicity in Salmonella of a Simulated Urban-Smog Atmosphere Generated Using a Mobile Reaction Chamber

    Science.gov (United States)

    The EPA Mobile Reaction Chamber (MRC) is a 24-foot trailer containing a 14.3-m3 Teflon lined photochemical chamber used to generate simulated urban atmospheres. Photochemistry in the MRC is catalyzed by 120 fluorescent bulbs evenly mixed with black light bulbs and UV bulbs (300 &...

  20. A plant chamber system with downstream reaction chamber to study the effects of pollution on biogenic emissions.

    Science.gov (United States)

    Timkovsky, J; Gankema, P; Pierik, R; Holzinger, R

    2014-01-01

    A system of two plant chambers and a downstream reaction chamber has been set up to investigate the emission of biogenic volatile organic compounds (BVOCs) and possible effects of pollutants such as ozone. The system can be used to compare BVOC emissions from two sets of differently treated plants, or to study the photochemistry of real plant emissions under polluted conditions without exposing the plants to pollutants. The main analytical tool is a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) which allows online monitoring of biogenic emissions and chemical degradation products. The identification of BVOCs and their oxidation products is aided by cryogenic trapping and subsequent in situ gas chromatographic analysis.

  1. Neutronics and activation of the preliminary reaction chamber of HiPER reactor based in a SCLL blanket

    Energy Technology Data Exchange (ETDEWEB)

    Juárez, Rafael, E-mail: rafael.juarez@upm.es [Instituto de Fusión Nuclear, UPM, Madrid (Spain); Escuela Técnica Superior de Ingenieros Industriales, UNED, Madrid (Spain); Sanz, Javier; Lopez-Revelles, A.J. [Escuela Técnica Superior de Ingenieros Industriales, UNED, Madrid (Spain); Perlado, José Manuel [Instituto de Fusión Nuclear, UPM, Madrid (Spain)

    2013-10-15

    Highlights: • Neutronic study of a proposal of a reaction chamber for HiPER reactor. • Two options for the blanket size, thin and thick, are studied and compared. • The thin blanket performs better than the thick blanket. • The proposed Vacuum Vessel is unviable as lifetime component in both cases. • Likely solutions for the Vacuum Vessel lifetime extension are explored. -- Abstract: The HiPER reactor design is exploring different reaction chambers. In this study, we tackle the neutronics and activation studies of a preliminary reaction chamber based in the following technologies: unprotected dry wall for the First Wall, self-cooled lead lithium blanket, and independent low activation steel Vacuum Vessel. The most critical free parameter in this stage is the blanket thickness, as a function of the {sup 6}Li enrichment. After a parametric study, we select for study both a “thin” and “thick” blanket, with “high” and “low” {sup 6}Li enrichment respectively, to reach a TBR = 1.1. To help to make a choice, we compute, for both blanket options, in addition to the TBR, the energy amplification factor, the tritium partial pressure, the {sup 203}Hg and {sup 210}Po total activity in the LiPb loop, and the Vacuum Vessel thickness required to guarantee the reweldability during its lifetime. The thin blanket shows a superior performance in the safety related issues and structural viability, but it operates at higher {sup 6}Li enrichment. It is selected for further improvements. The Vacuum Vessel shows to be unviable in both cases, with the thickness varying between 39 and 52 cm. Further chamber modifications, such as the introduction of a neutron reflector, are required to exploit the benefits of the thin blanket with a reasonable Vacuum Vessel.

  2. Type I ELM filament heat fluxes on the KSTAR main chamber wall

    Directory of Open Access Journals (Sweden)

    M.-K. Bae

    2017-08-01

    Full Text Available Heat loads deposited on the first wall by mitigated Type I ELMs are expected to be the dominant contributor to the total thermal plasma wall load of the International Thermonuclear Experimental Reactor (ITER, particularly in the upper main chamber regions during the baseline H-mode magnetic equilibrium, due to the fast radial convective heat propagation of ELM filaments before complete loss to the divertor. Specific Type I ELMing H-mode discharges have been performed with a lower single null magnetic geometry, where the outboard separatrix position is slowly (∼7s scanned over a radial distance of 7cm, reducing the wall probe–separatrix distance to a minimum of ∼9cm, and allowing the ELM filament heat loss to the wall to be analyzed as a function of radial propagation distance. A fast reciprocating probe (FRP head is separately held at fixed position toroidally close and 4.7cm radially in front of the wall probe. This FRP monitors the ELM ion fluxes, allowing an average filament radial propagation speed, found to be independent of ELM energy, of 80–100ms−1 to be extracted. Radial dependence of the peak filament wall parallel heat flux is observed to be exponential, with the decay length of λq, ELM ∼25 ± 4mm and with the heat flux of q∥, ELM= 0.05MWm−2 at the wall, corresponding to q∥ ∼ 7.5MWm−2 at the second separatrix. Along with the measured radial propagation speed and the calculated radial profile of the magnetic connection lengths across the SOL, these data could be utilized to analyze filament energy loss model for the future machines.

  3. A new visible spectroscopy diagnostic for the JET ITER-like wall main chamber

    OpenAIRE

    Maggi, C. F.; Brezinsek, S.; Zastrow, K.-D.; JET-EFDA Contributors; Stamp, M. F.; Griph, S.; Heesterman, P.; Hogben, C.; Horton, A.; Meigs, A.; Morlock, C.; Studholme, W.

    2012-01-01

    In preparation for ITER, JET has been upgraded with a new ITER-like wall (ILW), whereby the main plasma facing components, previously of carbon, have been replaced by mainly Be in the main chamber and W in the divertor. As part of the many diagnostic enhancements, a new, survey, visible spectroscopy diagnostic has been installed for the characterization of the ILW. An array of eight lines-of-sight (LOS) view radially one of the two JET neutral beam shine through areas (W coated carbon fibre c...

  4. Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber

    KAUST Repository

    Shi, Xian

    2017-01-05

    Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber are numerically investigated using an 1-D unsteady, shock-capturing, compressible and reacting flow solver. Different combinations of reaction front propagation and end-gas combustion modes are observed, i.e., 1) deflagration without end-gas combustion, 2) deflagration to end-gas autoignition, 3) deflagration to end-gas detonation, 4) developing or developed detonation, occurring in the sequence of increasing initial temperatures. Effects of ignition location and chamber size are evaluated: the asymmetric ignition is found to promote the reactivity of unburnt mixture compared to ignitions at center/wall, due to additional heating from asymmetric pressure waves. End-gas combustion occurs earlier in smaller chambers, where end-gas temperature rise due to compression heating from the deflagration is faster. According to the ξ−ε regime diagram based on Zeldovich theory, modes of reaction front propagation are primarily determined by reactivity gradients introduced by initial ignition, while modes of end-gas combustion are influenced by the total amount of unburnt mixture at the time when autoignition occurs. A transient reactivity gradient method is provided and able to capture the occurrence of detonation.

  5. Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber

    KAUST Repository

    Shi, Xian; Ryu, Je Ir; Chen, Jyh-Yuan; Dibble, Robert W.

    2017-01-01

    Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber are numerically investigated using an 1-D unsteady, shock-capturing, compressible and reacting flow solver. Different combinations of reaction front propagation and end-gas combustion modes are observed, i.e., 1) deflagration without end-gas combustion, 2) deflagration to end-gas autoignition, 3) deflagration to end-gas detonation, 4) developing or developed detonation, occurring in the sequence of increasing initial temperatures. Effects of ignition location and chamber size are evaluated: the asymmetric ignition is found to promote the reactivity of unburnt mixture compared to ignitions at center/wall, due to additional heating from asymmetric pressure waves. End-gas combustion occurs earlier in smaller chambers, where end-gas temperature rise due to compression heating from the deflagration is faster. According to the ξ−ε regime diagram based on Zeldovich theory, modes of reaction front propagation are primarily determined by reactivity gradients introduced by initial ignition, while modes of end-gas combustion are influenced by the total amount of unburnt mixture at the time when autoignition occurs. A transient reactivity gradient method is provided and able to capture the occurrence of detonation.

  6. Conceptual design of a fast-ignition laser fusion reactor based on a dry wall chamber

    International Nuclear Information System (INIS)

    Ogawa, Y; Goto, T; Okano, K; Asaoka, Y; Hiwatari, R; Someya, Y

    2008-01-01

    The fast ignition is quite attractive for a compact laser fusion reactor, because a sufficiently high pellet gain is available with a small input energy. We designed an inertial fusion reactor based on Fast-ignition Advanced Laser fusion reactor CONcept, called FALCON-D, where a dry wall is employed for a chamber wall. A simple point model shows that the pellet gain G∼100 is available with laser energies of 350kJ for implosion, 50kJ for heating. This results in the fusion yield of 40 MJ in one shot. By increasing the repetition rate up to 30 Hz, the fusion power of 1.2 GWth becomes available. Plant system analysis shows the net electric power to be about 0.4 GWe In the fast ignition it is available to employ a low aspect ratio pellet, which is favorable for the stability during the implosion phase. Here the pellet aspect ratio is reduced to be 2 ∼ 4, and the optimization of the pulse shape for the implosion laser are carried out by using the 1-D hydrodynamic simulation code ILESTA-1D. A ferritic steel with a tungsten armour is employed for the chamber wall. The feasibility of this dry wall concept is studied from various engineering aspects such as surface melting, physical and chemical sputtering, blistering and exfoliation by helium retention, and thermo-mechanical fatigue, and it is found that blistering and exfoliation due to the helium retention and fatigue failure due to cyclic thermal load are major concerns. The cost analysis shows that the construction cost is moderate but the cost of electricity is slightly expensive

  7. Conceptual design of a fast-ignition laser fusion reactor based on a dry wall chamber

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Y [High Temperature Plasma Center, University of Tokyo, Chiba (Japan); Goto, T; Okano, K [Graduate School of Frontier Sciences, University of Tokyo, Chiba (Japan); Asaoka, Y; Hiwatari, R [Central Research Institute for Electric Power Industry, Komae, Tokyo (Japan); Someya, Y [Graduate School of Engineering, Musashi Institute of Technology, Tokyo (Japan)], E-mail: ogawa@ppl.k.u-tokyo.ac.jp

    2008-05-15

    The fast ignition is quite attractive for a compact laser fusion reactor, because a sufficiently high pellet gain is available with a small input energy. We designed an inertial fusion reactor based on Fast-ignition Advanced Laser fusion reactor CONcept, called FALCON-D, where a dry wall is employed for a chamber wall. A simple point model shows that the pellet gain G{approx}100 is available with laser energies of 350kJ for implosion, 50kJ for heating. This results in the fusion yield of 40 MJ in one shot. By increasing the repetition rate up to 30 Hz, the fusion power of 1.2 GWth becomes available. Plant system analysis shows the net electric power to be about 0.4 GWe In the fast ignition it is available to employ a low aspect ratio pellet, which is favorable for the stability during the implosion phase. Here the pellet aspect ratio is reduced to be 2 {approx} 4, and the optimization of the pulse shape for the implosion laser are carried out by using the 1-D hydrodynamic simulation code ILESTA-1D. A ferritic steel with a tungsten armour is employed for the chamber wall. The feasibility of this dry wall concept is studied from various engineering aspects such as surface melting, physical and chemical sputtering, blistering and exfoliation by helium retention, and thermo-mechanical fatigue, and it is found that blistering and exfoliation due to the helium retention and fatigue failure due to cyclic thermal load are major concerns. The cost analysis shows that the construction cost is moderate but the cost of electricity is slightly expensive.

  8. Conceptual design of a fast-ignition laser fusion reactor based on a dry wall chamber

    Science.gov (United States)

    Ogawa, Y.; Goto, T.; Okano, K.; Asaoka, Y.; Hiwatari, R.; Someya, Y.

    2008-05-01

    The fast ignition is quite attractive for a compact laser fusion reactor, because a sufficiently high pellet gain is available with a small input energy. We designed an inertial fusion reactor based on Fast-ignition Advanced Laser fusion reactor CONcept, called FALCON-D, where a dry wall is employed for a chamber wall. A simple point model shows that the pellet gain G~100 is available with laser energies of 350kJ for implosion, 50kJ for heating. This results in the fusion yield of 40 MJ in one shot. By increasing the repetition rate up to 30 Hz, the fusion power of 1.2 GWth becomes available. Plant system analysis shows the net electric power to be about 0.4 GWe In the fast ignition it is available to employ a low aspect ratio pellet, which is favorable for the stability during the implosion phase. Here the pellet aspect ratio is reduced to be 2 ~ 4, and the optimization of the pulse shape for the implosion laser are carried out by using the 1-D hydrodynamic simulation code ILESTA-1D. A ferritic steel with a tungsten armour is employed for the chamber wall. The feasibility of this dry wall concept is studied from various engineering aspects such as surface melting, physical and chemical sputtering, blistering and exfoliation by helium retention, and thermo-mechanical fatigue, and it is found that blistering and exfoliation due to the helium retention and fatigue failure due to cyclic thermal load are major concerns. The cost analysis shows that the construction cost is moderate but the cost of electricity is slightly expensive.

  9. Target activation and radiological response of ARIES-IFE dry wall chamber

    International Nuclear Information System (INIS)

    El-Guebaly, L.A.; Henderson, D.L.; Wilson, P.P.H.; Abdou, A.E.

    2002-01-01

    The choice of target coating and hohlraum wall materials is among the most critical decisions to be made for inertial fusion energy (IFE) designs. Gold and gold/gadolinium have long been considered to be the coating and hohlraum wall materials of choice for direct drive (DD) and indirect drive (ID) targets, respectively, offering high target performance and low beam energy losses. More recently, a variety of other materials have been considered, including W, Pb, Pt, Pd, and Ag for the DD target coating and Au, W, Pb, Hg, Ta, Cs, and Hf for the hohlraum wall of the ID target. The choice of the coating/hohlraum material is a tradeoff between the target design elements such as safety, target physics, economics, etc. We identified the key safety issues and have investigated the neutron-induced irradiation effects of the candidate coating/hohlraum materials using the radiation chamber conditions of the ARIES-IFE dry wall concept. The safety requirements have specific impacts in terms of the coating/hohlraum materials choice

  10. Chamber and Wall Response to Target Implosion in Inertial and Z-Pinch Fusion and Lithography Devices

    International Nuclear Information System (INIS)

    Hassanein, A.; Konkashbaev, I.; Morozov, V.; Sizyuk, V.

    2006-01-01

    The chamber walls, both solid and liquid, in inertial fusion energy (IFE) and Z-pinch reactors and Lithography devices are exposed to harsh conditions following each target implosion or pinching of plasma. Key issues of the cyclic IFE operation include intense photon and ion deposition, wall thermal and hydrodynamic evolution, wall erosion and fatigue lifetime, and chamber clearing and evacuation to ensure desirable conditions prior to target implosion. Detailed models have been developed for reflected laser light, emitted photons, neutrons, and target debris deposition and interaction with chamber components and have been implemented in the comprehensive HEIGHTS software package. The hydrodynamic response of chamber walls in bare or in gas-filled cavities and the photon transport of the deposited energy has been calculated by means of new and advanced numerical techniques for accurate shock treatment and propagation. These models include detail media hydrodynamics, non-LTE multi-group for both continuum and line radiation transport, and dynamics of eroded debris resulting from the intense energy deposition. The focus of this study is to critically assess the reliability and the dynamic response of chamber walls in various proposed protection methods for IFE systems. Key requirements are that: (i) the chamber wall accommodates the cyclic energy deposition while providing the required lifetime due to various erosion mechanisms, such as vaporization, chemical and physical sputtering, melt/liquid splashing and explosive erosion, and fragmentation of liquid walls, and (ii) after each shot the chamber is cleared and returned to a quiescent state in preparation for the target injection and the firing of the driver for the subsequent shot. This paper investigates in details these two important issues and found that the required operating frequency of the IFE reactors for power production may be severely limited due to these two requirements. (author)

  11. A new visible spectroscopy diagnostic for the JET ITER-like wall main chamber

    International Nuclear Information System (INIS)

    Maggi, C. F.; Brezinsek, S.; Stamp, M. F.; Griph, S.; Heesterman, P.; Hogben, C.; Horton, A.; Meigs, A.; Studholme, W.; Zastrow, K.-D.; Morlock, C.

    2012-01-01

    In preparation for ITER, JET has been upgraded with a new ITER-like wall (ILW), whereby the main plasma facing components, previously of carbon, have been replaced by mainly Be in the main chamber and W in the divertor. As part of the many diagnostic enhancements, a new, survey, visible spectroscopy diagnostic has been installed for the characterization of the ILW. An array of eight lines-of-sight (LOS) view radially one of the two JET neutral beam shine through areas (W coated carbon fibre composite tiles) at the inner wall. In addition, one vertical LOS views the solid W tile at the outer divertor. The light emitted from the plasma is coupled to a series of compact overview spectrometers, with overall wavelength range of 380–960 nm and to one high resolution Echelle overview spectrometer covering the wavelength range 365–720 nm. The new survey diagnostic has been absolutely calibrated in situ by means of a radiometric light source placed inside the JET vessel in front of the whole optical path and operated by remote handling. The diagnostic is operated in every JET discharge, routinely monitoring photon fluxes from intrinsic and extrinsic impurities (e.g., Be, C, W, N, and Ne), molecules (e.g., BeD, D 2 , ND) and main chamber and divertor recycling (typically Dα, Dβ, and Dγ). The paper presents a technical description of the diagnostic and first measurements during JET discharges.

  12. Transverse resistive wall instability of an off-axis ribbon beam in a circular chamber

    International Nuclear Information System (INIS)

    Courant, E.D.; Month, M.

    1978-06-01

    High energy proton storage rings are designed to make maximal use of the available vacuum chamber aperture. This is dictated primarily by economic considerations. The accumulation of current in a typical high energy ring creates a rather unusual beam configuration: in particular, a ribbon beam in a circular chamber set well off the central axis. The result is an enhanced resistive wall instability. This could be anticipated from the strong dependence of the current threshold on the chamber radius for a centered beam. For an off-centered beam, one might expect that the relevant replacement for the radius would be the distance of closest approach. The case of a wide ribbon-type beam is treated. The current threshold is obtained as a solution to a coupled oscillator eigenvalue problem. When the beam is small as occurs near the beginning of current stack formation, the problem is reduced to a dispersion relation. Results are expressed in terms of ISABELLE parameters. Some conclusions relevant to the ISABELLE design are presented

  13. Open-air ionisation chambers with walls of soft-tissue equivalent material for measuring photon doses

    International Nuclear Information System (INIS)

    Vialettes, H.; Anceau, J.C.; Grand, M.; Petit, G.

    1968-01-01

    The ionisation chambers presented in this report constitute a contribution to research into methods of carrying out correct determinations in the field of health physics. The use of a mixture of teflon containing 42.5 per cent by weight of carbon for the chamber walls makes it possible to measure directly the dose absorbed in air through 300 mg/cm 2 of soft tissue and, consequently, the dose absorbed in the soft tissues with a maximum error of 10 per cent for photon energies of between 10 keV and 10 MeV. Furthermore since this material does not contain hydrogen, the chamber has a sensitivity to neutrons which is much less than other chambers in current use. Finally the shape of these chambers has been studied with a view to obtaining a satisfactory measurement from the isotropy point of view; for example for gamma radiation of 27 keV, the 3 litre chamber is isotropic to within 10 per cent over 270 degrees, and the 12 litre chamber is isotropic to within 10 per cent over 300 degrees; for 1.25 MeV gamma radiation this range is extended over 330 degrees for the 3 litre chamber, and 360 degrees for the 12 litre chamber. This report presents the measurements carried out with these chambers as well as the results obtained. These results are then compared to those obtained with other chambers currently used in the field of health physics. (authors) [fr

  14. The FAA altitude chamber training flight profile : a survey of altitude reactions, 1965-1989.

    Science.gov (United States)

    1990-09-01

    Reactions from 1,161 trainees out of 12,759 trainees subjected to the FAA altitude chamber training flights from 1965-1989 are annotated in this survey. Although there were some mild and expected reactions, these training profiles appear to provide a...

  15. Striatal lesions produce distinctive impairments in reaction time performance in two different operant chambers.

    Science.gov (United States)

    Brasted, P J; Döbrössy, M D; Robbins, T W; Dunnett, S B

    1998-08-01

    The dorsal striatum plays a crucial role in mediating voluntary movement. Excitotoxic striatal lesions in rats have previously been shown to impair the initiation but not the execution of movement in a choice reaction time task in an automated lateralised nose-poke apparatus (the "nine-hole box"). Conversely, when a conceptually similar reaction time task has been applied in a conventional operant chamber (or "Skinner box"), striatal lesions have been seen to impair the execution rather than the initiation of the lateralised movement. The present study was undertaken to compare directly these two results by training the same group of rats to perform a choice reaction time task in the two chambers and then comparing the effects of a unilateral excitotoxic striatal lesion in both chambers in parallel. Particular attention was paid to adopting similar parameters and contingencies in the control of the task in the two test chambers. After striatal lesions, the rats showed predominantly contralateral impairments in both tasks. However, they showed a deficit in reaction time in the nine-hole box but an apparent deficit in response execution in the Skinner box. This finding confirms the previous studies and indicates that differences in outcome are not simply attributable to procedural differences in the lesions, training conditions or tasks parameters. Rather, the pattern of reaction time deficit after striatal lesions depends critically on the apparatus used and the precise response requirements for each task.

  16. SCALP: Scintillating ionization chamber for ALPha particle production in neutron induced reactions

    Science.gov (United States)

    Galhaut, B.; Durand, D.; Lecolley, F. R.; Ledoux, X.; Lehaut, G.; Manduci, L.; Mary, P.

    2017-09-01

    The SCALP collaboration has the ambition to build a scintillating ionization chamber in order to study and measure the cross section of the α-particle production in neutron induced reactions. More specifically on 16O and 19F targets. Using the deposited energy (ionization) and the time of flight measurement (scintillation) with a great accuracy, all the nuclear reaction taking part on this project will be identify.

  17. Fusion energy research with lasers, direct drive targets, and dry wall chambers

    International Nuclear Information System (INIS)

    Sethian, J.D.; Obenschain, S.P.; Myers, M.

    2003-01-01

    We are carrying out a coordinated, focused effort to develop Laser Inertial Fusion Energy. The key components are developed in concert with one another and the science and engineering issues are addressed concurrently. Significant progress has been made in this program: We are evaluating target designs that show it could be possible to achieve the high gains (>100) needed for a practical fusion system. These have a low density CH foam that is wicked with solid DT, and over coated with a thin high-Z layer. Significant advances have been made with the two types of laser are being developed: Krypton Fluoride (KrF) gas lasers and Diode Pumped Solid State Lasers (DPPSL). Both have the potential to meet the fusion energy requirements for rep-rate, efficiency, durability and cost. This paper also presents the advances in development of chamber operating windows (target survival plus no wall erosion), final optics (aluminum at grazing incidence has high reflectivity and exceeds required laser damage threshold), target fabrication (advanced foams and high Z overcoats), and target injection (new facility for target injection and tracking studies). (author)

  18. Optical design of a reaction chamber for weakly absorbed light. II. Parallel mirrors, multitravel

    International Nuclear Information System (INIS)

    Devaney, J.J.; Finch, F.T.

    1975-06-01

    This report outlines the possibilities to be found using one or more diffraction-limited high-quality light beams to activate a weakly absorbing gas in a regime where the diffraction spread can be controlled by converging optical devices to within a ratio of √2 of the minimum at the beam waist (corresponding lengths between converging elements are within twice the Rayleigh range). Our designs use plane or cylindrical parallel mirrors down which a light beam is repeatedly reflected. In the first design variation, the beam is re-reflected up the parallel mirrors to the entrance aperture where it can be returned repeatedly for a number of multiply reflecting ''travels'' up and down the parallel mirror reaction chamber. In the second variation, the return of the beam after each multiply reflecting ''travel'' down the chamber is external to the chamber and is achieved by two mirror reflections. For diffraction control the return mirrors can be made converging. For multiple laser excitation, any of the external return mirrors can be replaced by a laser. The advantage of these designs is a high degree of uniformity of chamber illumination with a reasonably high number of passes. Drawbacks of the designs are the large space needed for beam return (many tens of meters for some parameters) and (common to all high optical quality chambers) the figuring and reflectivity demands on the mirrors. (U.S.)

  19. Numerical investigations of cooling holes system role in the protection of the walls of a gas turbine combustion chamber

    Energy Technology Data Exchange (ETDEWEB)

    Ben Sik Ali, Ahlem; Kriaa, Wassim; Mhiri, Hatem [Ecole Nationale D' Ingenieurs de Monastir, Unite de Thermique et Thermodynamique des Procedes industriels, Monastir (Tunisia); Bournot, Philippe [IUSTI, UMR CNRS 6595, Marseille (France)

    2012-05-15

    Numerical simulations in a gas turbine Swirl stabilized combustor were conducted to investigate the effectiveness of a cooling system in the protection of combustor walls. The studied combustion chamber has a high degree of geometrical complexity related to the injection system as well as the cooling system based on a big distribution of small holes (about 3,390 holes) bored on the flame tube walls. Two cases were considered respectively the flame tube without and with its cooling system. The calculations were carried out using the industrial CFD code FLUENT 6.2. The various simulations made it possible to highlight the role of cooling holes in the protection of the flame tube walls against the high temperatures of the combustion products. In fact, the comparison between the results of the two studied cases demonstrated that the walls temperature can be reduced by about 800 C by the mean of cooling holes technique. (orig.)

  20. Carbonylative Heck Reactions Using CO Generated ex Situ in a Two-Chamber System

    DEFF Research Database (Denmark)

    Hermange, Philippe; Gøgsig, Thomas; Lindhardt, Anders Thyboe

    2011-01-01

    A carbonylative Heck reaction of aryl iodides and styrene derivatives employing a two-chamber system using a stable, crystalline, and nontransition metal based carbon monoxide source is reported. By applying near-stoichiometric amounts of the carbon monoxide precursor, an effective exploitation o...... of the hazardous CO gas is obtained affording chalcone derivatives in good yields. Application to isotope labeling, incorporating 13CO, was further established....

  1. Gridded ionization chamber and dual parameter measurement system for fast neutron-induced charged particles emission reaction

    International Nuclear Information System (INIS)

    Chen Yingtang; Qi Huiquan; Chen Zemin

    1995-01-01

    A twin ionization chamber with a common cathode and grids is described for (n,α), (n,p) studies. The chamber is used to determine the energy spectra and angular distribution of the charged particles emitted from the sample positioned on the cathode by dual parameter measurements of coinciding pulses from the anode and cathode of the ionization chamber. Pu α source is used to test the property of the chamber, an isotropic angular distribution is basically showed and the energy resolution is about 2%. This ionization chamber has already been applied to the studies of the 40 Ca(n,α) and 64 Zn(n,α) reactions

  2. Simulated reaction of formaldehyde and ambient atmospheric particulate matter using a chamber

    Institute of Scientific and Technical Information of China (English)

    Yueyue Chen; Jia Liu; Jing Shang; Tong Zhu

    2017-01-01

    The reaction of HCHO with Beijing winter's real ambient particulate matter (PM) inside a 3.3 m3 Teflon Chamber was conducted in this study.NO2,O3 and H2O gases were removed from the ambient aerosol before entering into the chamber.The decays of HCHO were monitored (acetylacetone spectrophotometry method) during the reactions at different PM number concentrations (Na) and relative humidities (RHs),and the formed particulate formate was detected by IC and XPS techniques.The results showed that when RH was 10%-15%,the decay rate of HCHO in the chamber was higher with the existence of PM from relatively clean days (with number concentration (Na) < 200,000 particle/L,0.35-22.5 μm) compared to dirty days (Na > 200,000 particle/L,0.35-22.5 μm).When RH increased to 30%-45%,PM can hardly have significant influences on the decay of HCHO.The formations of formate on the reacted PM were consistent with the HCHO decay rates at different ambient PM Na and RH conditions.This is a first study related to the "real" ambient PM reacted with HCHO and suggested that in the clean and low RH days,PM could be an effective medium for the conversion of HCHO to formate.

  3. Evaporation and condensation heat transfer in a suppression chamber of the water wall type passive containment cooling system

    International Nuclear Information System (INIS)

    Fujii, Tadashi; Kataoka, Yoshiyuki; Murase, Michio

    1996-01-01

    To evaluate the system pressure response of a water wall type containment cooling system, which is one of the passive safety systems, the evaporation and condensation behaviors in a suppression chamber have been experimentally examined. In the system, the suppression pool water evaporates from the pool surface, passing into the wetwell due to pool temperature rise, while steam in the wetwell condenses on the steel containment vessel wall due to the heat release through the wall. The wetwell is a gas phase region in the suppression chamber and its pressure, which is expressed as the sum of the noncondensable gas pressure and saturated steam pressure, is strongly affected by the evaporation heat transfer from the suppression pool surface and condensation heat transfer on the containment vessel wall. Based on the measured temperature profiles near the heat transfer surface and the wetwell pressure using two apparatuses, evaporation and condensation heat transfer coefficients were evaluated. The following results were obtained. (1) Both heat transfer coefficients increased as the ratio of the steam partial pressure to the total pressure increased. (2) Comparison of the results from two types of test apparatuses confirmed that the size of the heat transfer surface did not affect the heat transfer characteristics within these tests. (3) The heat transfer coefficients were expressed by the ratio of the steam to noncondensable gas logarithmic mean concentration, which considered the steam and gas concentration gradient from the heat transfer surface to the wetwell bulk. (author)

  4. Operation method for wall surface of pressure suppression chamber of reactor container and floating scaffold used for the method

    International Nuclear Information System (INIS)

    Matsuzaki, Tetsuo; Kounomaru, Toshimi; Saito, Koichi.

    1996-01-01

    A floating scaffold is provisionally disposed in adjacent with the wall surface of pool water of a pressure suppression chamber while being floated on the surface of the pool water before the drainage of the pool water from the pressure vessel. The floating scaffold has guide rollers sandwiching a bent tube of an existent facility so that the horizontal movement is restrained, and is movable only in a vertical direction depending on the change of water level of the pool water. In addition, a handrail for preventing dropping, and a provisional illumination light are disposed. When pool water in the pressure suppression chamber is drained, the water level of the pool water is lowered in accordance with the amount of drained water. The floating scaffold floating on the water surface is lowered while being guided by the bent tube, and the operation position is lowered. An operator riding on the floating scaffold inspects the wall surfaces of the pressure chamber and conducts optional repair and painting. (I.N.)

  5. Optimization of phase analysis of refractory alloys in the gas-ion-reaction chamber

    International Nuclear Information System (INIS)

    Blumenkamp, H.J.; Hoven, H.; Koizlik, K.; Nickel, H.

    1980-04-01

    Reactor components outside the core which are under high thermal and mechanical stresses are made from refractory alloys. For basic research and for quality control, these materials are investigated by metallography, which is an independent group of characterization procedures as well as basis for many other methods. An important way of increasing the information about a material yielded by metallography is the expansions of phase contrast, in particular the phase contrasting in the gas-ion-reaction chamber. In this paper, the experimental procedure is described and the process of optimizing the procedure with respect to the Ni- and Fe-based refractory alloys examined in the IRW is discussed. (orig.) [de

  6. Chamber science and technology key question No.1: liquid walls in MFE and IFE

    International Nuclear Information System (INIS)

    Moir, R.; Morley, N.

    1999-01-01

    For some time now people have thought of liquid walls as an attractive solution to the technology problems of high power density plasma configurations for MFE, and as (nearly) essential for the pulsed wall-loading conditions in IFE. A flowing, renewable surface could be eroded, evaporated and even be broken apart with no permanent adverse effects on a structure requiring frequent maintenance and replacement. Alpha particle energy could be removed without conduction through a solid wall and the associated thermal stress and creep failure modes, and the energy could be extracted at high temperatures for efficient energy conversion. If a liquid wall of sufficient depth could be formed, radiation damage and waste disposal issues for solid structures could be significantly ameliorated. All these benefits are indeed possible, if only liquid walls could be made to work. As we will see, there are many issues associated with the successful and attractive implementation of liquid walls

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

    International Nuclear Information System (INIS)

    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

    2012-01-01

    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.

  8. Evaluation of thermal stress in the anode chamber wall of a large volume magnetic bucket ion source

    International Nuclear Information System (INIS)

    Wells, Russell; Horiike, Hiroshi; Kuriyama, Masaaki; Ohara, Yoshihiro

    1984-02-01

    Thermal stress analysis was performed on the plasma chamber of the Large Volume Magnetic Multipole Bucket Ion Source (LVB) designed for use on the JT-60 NBI system. The energy absorbed by the walls of the plasma chambers of neutral beam injectors is of the order of 1% of the accelerator electrical drain power. A previous study indicates that a moderately high heat flux, of about 600W/cm 2 , is concentrated on the magnetic field cusp lines during normal full power operation. Abnormal arc discharges during conditioning of a stainless steel LVB produced localized melting of the stainless steel at several locations near the cusps lines. The power contained in abnormal arc discharges (arc spots) was estimated from the observed melting. Thermal stress analysis was performed numerically on representative sections of the copper LVB design for both stable and abnormal arc discharge conditions. Results show that this chamber should not fail due to thermal fatigue stesses arising from normal arc discharges. However, fatigue failure may occur after several hundred to a few thousand arc spots of 30mS duration at any one location. Limited arc discharge operation of the copper bucket was performed to partially verify the chamber's durability. (author)

  9. Granular flow considerations in the design of a cascade solid breeder reaction chamber

    International Nuclear Information System (INIS)

    Walton, O.R.

    1983-10-01

    Both horizontally and vertically oriented rotating chambers with granular material held on the inner surface by centrifugal action are examined. Modifications to the condition for controlled quasi-static flow on an incline plane, phi/sub w/ 0 +- 10 0 for ceramic particles and metal surfaces. For vertical orientations the maximum half-angle of the top cone is slightly less than the wall friction angle phi/sub w/ while the lower portion can have a half angle as large as (90 0 - phi/sub w). Percolation of fines through shearing granular solids is briefly discussed and recommended experimental and calculational studies to obtain a better understanding of this behavior are described

  10. New model of chlorine-wall reaction for simulating chlorine concentration in drinking water distribution systems.

    Science.gov (United States)

    Fisher, Ian; Kastl, George; Sathasivan, Arumugam

    2017-11-15

    Accurate modelling of chlorine concentrations throughout a drinking water system needs sound mathematical descriptions of decay mechanisms in bulk water and at pipe walls. Wall-reaction rates along pipelines in three different systems were calculated from differences between field chlorine profiles and accurately modelled bulk decay. Lined pipes with sufficiently large diameters (>500 mm) and higher chlorine concentrations (>0.5 mg/L) had negligible wall-decay rates, compared with bulk-decay rates. Further downstream, wall-reaction rate consistently increased (peaking around 0.15 mg/dm 2 /h) as chlorine concentration decreased, until mass-transport to the wall was controlling wall reaction. These results contradict wall-reaction models, including those incorporated in the EPANET software, which assume wall decay is of either zero-order (constant decay rate) or first-order (wall-decay rate reduces with chlorine concentration). Instead, results are consistent with facilitation of the wall reaction by biofilm activity, rather than surficial chemical reactions. A new model of wall reaction combines the effect of biofilm activity moderated by chlorine concentration and mass-transport limitation. This wall reaction model, with an accurate bulk chlorine decay model, is essential for sufficiently accurate prediction of chlorine residuals towards the end of distribution systems and therefore control of microbial contamination. Implementing this model in EPANET-MSX (or similar) software enables the accurate chlorine modelling required for improving disinfection strategies in drinking water networks. New insight into the effect of chlorine on biofilm can also assist in controlling biofilm to maintain chlorine residuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Multi-Sampling Ionization Chamber (MUSIC) for measurements of fusion reactions with radioactive beams

    International Nuclear Information System (INIS)

    Carnelli, P.F.F.; Almaraz-Calderon, S.; Rehm, K.E.; Albers, M.; Alcorta, M.; Bertone, P.F.; Digiovine, B.; Esbensen, H.; Fernández Niello, J.; Henderson, D.; Jiang, C.L.; Lai, J.; Marley, S.T.; Nusair, O.; Palchan-Hazan, T.; Pardo, R.C.; Paul, M.; Ugalde, C.

    2015-01-01

    A detection technique for high-efficiency measurements of fusion reactions with low-intensity radioactive beams was developed. The technique is based on a Multi-Sampling Ionization Chamber (MUSIC) operating as an active target and detection system, where the ionization gas acts as both target and counting gas. In this way, we can sample an excitation function in an energy range determined by the gas pressure, without changing the beam energy. The detector provides internal normalization to the incident beam and drastically reduces the measuring time. In a first experiment we tested the performance of the technique by measuring the 10,13,15 C+ 12 C fusion reactions at energies around the Coulomb barrier

  12. Multi-Sampling Ionization Chamber (MUSIC) for measurements of fusion reactions with radioactive beams

    Energy Technology Data Exchange (ETDEWEB)

    Carnelli, P.F.F. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA, San Martín, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Almaraz-Calderon, S. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Rehm, K.E., E-mail: rehm@anl.gov [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Albers, M.; Alcorta, M.; Bertone, P.F.; Digiovine, B.; Esbensen, H. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Fernández Niello, J. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA, San Martín, Buenos Aires (Argentina); Universidad Nacional de San Martín, Campus Miguelete, B1650BWA San Martín, Buenos Aires (Argentina); Henderson, D.; Jiang, C.L. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Lai, J. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Marley, S.T.; Nusair, O.; Palchan-Hazan, T.; Pardo, R.C. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Paul, M. [Racah Institute of Physics, Hebrew University, Jerusalem (Israel); Ugalde, C. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2015-11-01

    A detection technique for high-efficiency measurements of fusion reactions with low-intensity radioactive beams was developed. The technique is based on a Multi-Sampling Ionization Chamber (MUSIC) operating as an active target and detection system, where the ionization gas acts as both target and counting gas. In this way, we can sample an excitation function in an energy range determined by the gas pressure, without changing the beam energy. The detector provides internal normalization to the incident beam and drastically reduces the measuring time. In a first experiment we tested the performance of the technique by measuring the {sup 10,13,15}C+{sup 12}C fusion reactions at energies around the Coulomb barrier.

  13. A large area position-sensitive ionization chamber for heavy-ion-induced reaction studies

    CERN Document Server

    Pant, L M; Dinesh, B V; Thomas, R G; Saxena, A; Sawant, Y S; Choudhury, R K

    2002-01-01

    A large area position-sensitive ionization chamber with a wide dynamic range has been developed to measure the mass, charge and energy of the heavy ions and the fission fragments produced in heavy-ion-induced reactions. The split anode geometry of the detector makes it suitable for both particle identification and energy measurements for heavy ions and fission fragments. The detector has been tested with alpha particles from sup 2 sup 4 sup 1 Am- sup 2 sup 3 sup 9 Pu source, fission fragments from sup 2 sup 5 sup 2 Cf and the heavy-ion beams from the 14UD Mumbai Pelletron accelerator facility. Using this detector, measurements on mass and total kinetic energy distributions in heavy-ion-induced fusion-fission reactions have been carried out for a wide range of excitation energies. Results on deep inelastic collisions and mass-energy correlations on different systems using this detector setup are discussed.

  14. Vessel Wall Reaction after Vena Cava Filter Placement

    International Nuclear Information System (INIS)

    Hoekstra, Arend; Elstrodt, Jan M.; Nikkels, Peter G.J.; Tiebosch, Anton T.M.G.

    2002-01-01

    Purpose: To evaluate the interaction between the Cordis Keeper vena caval filter and vessel wall in aporcine model.Methods: Implantation of the filter was performed in five pigs. Radiologic data concerning inferior vena cava(IVC) diameter and filter patency, filter leg span, and stability were collected. At 2 or 6 months post-implantation, histopathologic analysis of the IVC wall was performed.Results: All filters remained patent with no evidence of migration. However, at 6 months follow-up, two legs of one filter penetrated the vessel wall and were adherent to the liver. These preliminary results suggest that with the observed gradual increase in the filter span, the risk of caval wall penetration increases with time, especially in a relatively small IVC(average diameter 16 mm).Conclusion: The Cordis Keeper filter was well tolerated, but seems to be prone to caval wall penetration in the long term

  15. Tritons for the study of the charge-exchange reactions with the LHE streamer chamber: status and some possibilities

    International Nuclear Information System (INIS)

    Avramenko, S.A.; Belikov, Yu.A.; Golokhvastov, A.I.; Kirillov, A.D.; Khorozov, S.A.; Komolov, L.N.; Lukstin'sh, Yu.; Rukoyatkin, P.A.

    1997-01-01

    The 6 and 9 GeV/c secondary tritons, produced in the 4 He+A→ 3 H+X reaction, were used to study the charge-exchange reactions using a streamer chamber in magnetic field. The triton formation schemes, the beam parameters achieved as well as a way to reduce the beam momentum spread are given in the paper

  16. Reaction Rate Benchmark Experiments with Miniature Fission Chambers at the Slovenian TRIGA Mark II Reactor

    Science.gov (United States)

    Štancar, Žiga; Kaiba, Tanja; Snoj, Luka; Barbot, Loïc; Destouches, Christophe; Fourmentel, Damien; Villard, Jean-François AD(; )

    2018-01-01

    A series of fission rate profile measurements with miniature fission chambers, developed by the Commisariat á l'énergie atomique et auxénergies alternatives, were performed at the Jožef Stefan Institute's TRIGA research reactor. Two types of fission chambers with different fissionable coating (235U and 238U) were used to perform axial fission rate profile measurements at various radial positions and several control rod configurations. The experimental campaign was supported by an extensive set of computations, based on a validated Monte Carlo computational model of the TRIGA reactor. The computing effort included neutron transport calculations to support the planning and design of the experiments as well as calculations to aid the evaluation of experimental and computational uncertainties and major biases. The evaluation of uncertainties was performed by employing various types of sensitivity analyses such as experimental parameter perturbation and core reaction rate gradient calculations. It has been found that the experimental uncertainty of the measurements is sufficiently low, i.e. the total relative fission rate uncertainty being approximately 5 %, in order for the experiments to serve as benchmark experiments for validation of fission rate profiles. The effect of the neutron flux redistribution due to the control rod movement was studied by performing measurements and calculations of fission rates and fission chamber responses in different axial and radial positions at different control rod configurations. It was confirmed that the control rod movement affects the position of the maximum in the axial fission rate distribution, as well as the height of the local maxima. The optimal detector position, in which the redistributions would have minimum effect on its signal, was determined.

  17. Pulsed fusion space propulsion: Computational Magneto-Hydro Dynamics of a multi-coil parabolic reaction chamber

    Science.gov (United States)

    Romanelli, Gherardo; Mignone, Andrea; Cervone, Angelo

    2017-10-01

    Pulsed fusion propulsion might finally revolutionise manned space exploration by providing an affordable and relatively fast access to interplanetary destinations. However, such systems are still in an early development phase and one of the key areas requiring further investigations is the operation of the magnetic nozzle, the device meant to exploit the fusion energy and generate thrust. One of the last pulsed fusion magnetic nozzle design is the so called multi-coil parabolic reaction chamber: the reaction is thereby ignited at the focus of an open parabolic chamber, enclosed by a series of coaxial superconducting coils that apply a magnetic field. The field, beside confining the reaction and preventing any contact between hot fusion plasma and chamber structure, is also meant to reflect the explosion and push plasma out of the rocket. Reflection is attained thanks to electric currents induced in conductive skin layers that cover each of the coils, the change of plasma axial momentum generates thrust in reaction. This working principle has yet to be extensively verified and computational Magneto-Hydro Dynamics (MHD) is a viable option to achieve that. This work is one of the first detailed ideal-MHD analysis of a multi-coil parabolic reaction chamber of this kind and has been completed employing PLUTO, a freely distributed computational code developed at the Physics Department of the University of Turin. The results are thus a preliminary verification of the chamber's performance. Nonetheless, plasma leakage through the chamber structure has been highlighted. Therefore, further investigations are required to validate the chamber design. Implementing a more accurate physical model (e.g. Hall-MHD or relativistic-MHD) is thus mandatory, and PLUTO shows the capabilities to achieve that.

  18. IFE chamber dry wall materials response to pulsed X-rays and ions at power-plant level fluences

    Energy Technology Data Exchange (ETDEWEB)

    Renk, T.J. E-mail: tjrenk@sandia.gov; Olson, C.L.; Tanaka, T.J.; Ulrickson, M.A.; Rochau, G.A.; Peterson, R.R.; Golovkin, I.E.; Thompson, M.O.; Knowles, T.R.; Raffray, A.R.; Tillack, M.S

    2003-04-01

    We have begun a collaborative investigation of the response of candidate first-wall inertial fusion energy (IFE) reactor chamber drywall materials to X-rays on the Z facility, and to ions on RHEPP-1, both located at Sandia National Laboratories. Dose levels are comparable to those anticipated in future direct-drive reactors. Due to the 5-10 Hz repetition rate expected in such reactors, per-pulse effects such as material removal must be negligible. The primary wall materials investigated here are graphite and tungsten in various forms. After exposure on either RHEPP or Z, materials were analyzed for roughening and/or material removal (ablation) as a function of dose. Graphite is observed to undergo significant ablation/sublimation in response to ion exposure at the 3-4 J/cm{sup 2} level, significantly below doses expected in future dry-wall power plants. Evidence of thermomechanical stresses resulting in material loss occurs for both graphite and tungsten, and is probably related to the pulsed nature of the energy delivery. These effects are not seen in typical magnetic fusion energy (MFE) conditions where these same kinds of materials are used. Results are presented for thresholds below which no roughening or ablation occurs. Use of graphite in a 'velvet' two-dimensional form may mitigate the effects seen with the flat material, and alloying tungsten with rhenium may reduce its roughening due to the increased ductility of the alloy.

  19. Vessel wall reaction after vena cava filter placement

    NARCIS (Netherlands)

    Hoekstra, A; Elstrodt, JM; Nikkels, PGJ; Tiebosch, ATMG

    2002-01-01

    Purpose: To evaluate the interaction between the Cordis Keeper vena caval filter and vessel wall in a porcine model. Methods: Implantation of the filter was performed in five pigs. Radiologic data concerning inferior vena cava (IVC) diameter and filter patency, filter leg span, and stability were

  20. CFD modelling wall heat transfer inside a combustion chamber using ANSYS forte

    Science.gov (United States)

    Plengsa-ard, C.; Kaewbumrung, M.

    2018-01-01

    A computational model has been performed to analyze a wall heat transfer in a single cylinder, direct injection and four-stroke diesel engine. A direct integration using detailed chemistry CHEMKIN is employed in a combustion model and the Reynolds Averaged Navier Stokes (RANS) turbulence model is used to simulate the flow in the cylinder. To obtain heat flux results, a modified classical variable-density wall heat transfer model is also performed. The model is validated using experimental data from a CUMMINs engine operated with a conventional diesel combustion. One operating engine condition is simulated. Comparisons of simulated in-cylinder pressure and heat release rates with experimental data shows that the model predicts the cylinder pressure and heat release rates reasonably well. The contour plot of instantaneous temperature are presented. Also, the contours of predicted heat flux results are shown. The magnitude of peak heat fluxes as predicted by the wall heat transfer model is in the range of the typical measure values in diesel combustion.

  1. Modelling of action of X-ray radiation on cellular structures of walls of the chamber of pulse nuclear power devices

    International Nuclear Information System (INIS)

    Solov'ev, V.O.; Khristoforov, B.D.

    2008-01-01

    One elaborated both mathematical and test procedures to simulate wave processes in blasting chamber walls of the pulsed nuclear power plants under the strong X-ray irradiation by explosion and shock. The comparison results of the test and the calculated parameters of the shock waves under the explosion and the shock loading of different materials demonstrated their satisfactory compatibility. Making use of the elaborated procedures one investigated into behaviour of Li 17 Pb 83 made liquid heat-reflecting film at the explosion chamber wall when the evaporation caused recoil pulse was the load basic factor. One studied possibilities to reduce the explosion loads by changing of the charge lead cladding thickness and by making cellular structures and porous materials a part of chamber walls [ru

  2. A multi-component parallel-plate flow chamber system for studying the effect of exercise-induced wall shear stress on endothelial cells.

    Science.gov (United States)

    Wang, Yan-Xia; Xiang, Cheng; Liu, Bo; Zhu, Yong; Luan, Yong; Liu, Shu-Tian; Qin, Kai-Rong

    2016-12-28

    In vivo studies have demonstrated that reasonable exercise training can improve endothelial function. To confirm the key role of wall shear stress induced by exercise on endothelial cells, and to understand how wall shear stress affects the structure and the function of endothelial cells, it is crucial to design and fabricate an in vitro multi-component parallel-plate flow chamber system which can closely replicate exercise-induced wall shear stress waveforms in artery. The in vivo wall shear stress waveforms from the common carotid artery of a healthy volunteer in resting and immediately after 30 min acute aerobic cycling exercise were first calculated by measuring the inner diameter and the center-line blood flow velocity with a color Doppler ultrasound. According to the above in vivo wall shear stress waveforms, we designed and fabricated a parallel-plate flow chamber system with appropriate components based on a lumped parameter hemodynamics model. To validate the feasibility of this system, human umbilical vein endothelial cells (HUVECs) line were cultured within the parallel-plate flow chamber under abovementioned two types of wall shear stress waveforms and the intracellular actin microfilaments and nitric oxide (NO) production level were evaluated using fluorescence microscope. Our results show that the trends of resting and exercise-induced wall shear stress waveforms, especially the maximal, minimal and mean wall shear stress as well as oscillatory shear index, generated by the parallel-plate flow chamber system are similar to those acquired from the common carotid artery. In addition, the cellular experiments demonstrate that the actin microfilaments and the production of NO within cells exposed to the two different wall shear stress waveforms exhibit different dynamic behaviors; there are larger numbers of actin microfilaments and higher level NO in cells exposed in exercise-induced wall shear stress condition than resting wall shear stress condition

  3. Studies of tungsten erosion at the inner and outer main chamber wall of the ASDEX Upgrade tokamak

    Science.gov (United States)

    Tabasso, A.; Maier, H.; Roth, J.; Krieger, K.; ASDEX Upgrade Team

    2001-03-01

    A critical issue for the choice of main chamber first wall materials in future fusion devices such as ITER is the erosion rate due to bombardment by charge-exchange (CX) neutrals. Due to the relatively small flux density of impacting particles, respective measurements are only possible using long term samples (LTS) exposed for a full experimental campaign. In ASDEX Upgrade, CX erosion has been studied extensively for tungsten on the inner heat shield by placing four W coated tiles at different poloidal positions in one toroidal sector. During the same campaign, several LTS were placed at different poloidal and toroidal positions of the outer wall. 13C and Cu coated graphite probes were also used in order to test and compare W low and medium Z alternatives. The erosion results from the probes are compared with the calculated erosion [W. Eckstein, C. Garcia-Rosales, J. Roth, W. Ottenberger IPP Report, IPP 9/82]; [H. Verbeek, J. Stober, D. Coster, W. Eckstein, R. Schneider Nucl. Fus. 38 (1998) 12] and a figure of merit (F. of M.) between several materials is proposed which also takes into account the plasma isotope effect in CX erosion.

  4. Studies of tungsten erosion at the inner and outer main chamber wall of the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Tabasso, A.; Maier, H.; Roth, J.; Krieger, K.

    2001-01-01

    A critical issue for the choice of main chamber first wall materials in future fusion devices such as ITER is the erosion rate due to bombardment by charge-exchange (CX) neutrals. Due to the relatively small flux density of impacting particles, respective measurements are only possible using long term samples (LTS) exposed for a full experimental campaign. In ASDEX Upgrade, CX erosion has been studied extensively for tungsten on the inner heat shield by placing four W coated tiles at different poloidal positions in one toroidal sector. During the same campaign, several LTS were placed at different poloidal and toroidal positions of the outer wall. 13 C and Cu coated graphite probes were also used in order to test and compare W low and medium Z alternatives. The erosion results from the probes are compared with the calculated erosion [W. Eckstein, C. Garcia-Rosales, J. Roth, W. Ottenberger IPP Report, IPP 9/82]; [H. Verbeek, J. Stober, D. Coster, W. Eckstein, R. Schneider Nucl. Fus. 38 (1998) 12] and a figure of merit (F. of M.) between several materials is proposed which also takes into account the plasma isotope effect in CX erosion

  5. Testing an ionization chamber with gaseous samples and measurements of the (n, alpha) reaction cross sections

    CERN Document Server

    Gledenov, Yu M; Salatskii, V I; Sedyshev, P V; Andrzejewski, J; Szalanski, P

    1999-01-01

    A new ionization chamber with gaseous samples (GIC) has been designed and tested on the thermal and resonance neutron beams of FLNP's neutron sources. The exposed gas volume serves as a target for neutrons. The obtained thermal cross sections for the sup 1 sup 7 O(n, alpha) sup 1 sup 4 C, sup 2 sup 1 Ne(n, alpha) sup 1 sup 8 O and sup 3 sup 6 Ar(n, alpha) sup 3 sup 3 S reactions are (233+-12) mb, (0.18+-0.09) mb and (5.43+-0.27) mb, respectively. These measurements have been performed on a pure beam of thermal neutrons from the high flux reactor IBR-2; and they demonstrated high efficiency and reliability of the method. Compared to samples on substrates, the application of gaseous samples makes the beam background essentially lower, and what is more important, the background component is totally absent due to the absence of Li and B microimpurities in gaseous samples while they do present in the samples on substrates. The method is also applicable to measurements with resonance neutrons. The recovery capabili...

  6. Modeling of Uneven Flow and Electromagnetic Field Parameters in the Combustion Chamber of Liquid Rocket Engine with a Near-wall Layer Available

    Directory of Open Access Journals (Sweden)

    A. V. Rudinskii

    2015-01-01

    Full Text Available The paper concerns modeling of an uneven flow and electromagnetic field parameters in the combustion chamber of the liquid rocket engine with a near-wall layer available.The research objective was to evaluate quantitatively influence of changing model chamber mode of the liquid rocket engine on the electro-physical characteristics of the hydrocarbon fuel combustion by-products.The main method of research was based on development of a final element model of the flowing path of the rocket engine chamber and its adaptation to the boundary conditions.The paper presents a developed two-dimensional non-stationary mathematical model of electro-physical processes in the liquid rocket engine chamber using hydrocarbon fuel. The model takes into consideration the features of a gas-dynamic contour of the engine chamber and property of thermo-gas-dynamic characteristics of the ionized products of combustion of hydrocarbonic fuel. Distributions of magnetic field intensity and electric conductivity received and analyzed taking into account a low-temperature near-wall layer. Special attention is paid to comparison of obtained calculation values of the electric current, which is taken out from intrachamber space of the engine with earlier published data of other authors.

  7. Evaluation of Wall Correction Factor of INER's Air-Kerma Primary Standard Chamber and Dose Variation by Source Displacement for HDR 192Ir Brachytherapy

    Directory of Open Access Journals (Sweden)

    J. H. Lee

    2013-01-01

    Full Text Available The aim of the present study was to estimate the wall effect of the self-made spherical graphite-walled cavity chamber with the Monte Carlo method for establishing the air-kerma primary standard of high-dose-rate (HDR 192Ir brachytherapy sources at the Institute of Nuclear Energy Research (INER, Taiwan. The Monte Carlo method established in this paper was also employed to respectively simulate wall correction factors of the 192Ir air-kerma standard chambers used at the National Institute of Standards and Technology (NIST, USA and the National Physical Laboratory (NPL, UK for comparisons and verification. The chamber wall correction calculation results will be incorporated into INER's HDR 192Ir primary standard in the future. For the brachytherapy treatment in the esophagus or in the bronchi, the position of the isotope may have displacement in the cavity. Thus the delivered dose would differ from the prescribed dose in the treatment plan. We also tried assessing dose distribution due to the position displacement of HDR 192Ir brachytherapy source in a phantom with a central cavity by the Monte Carlo method. The calculated results could offer a clinical reference for the brachytherapy within the human organs with cavity.

  8. Neurocysticercosis presenting as isolated wall-eyed monocular internuclear ophthalmoplegia with contraversive ocular tilt reaction.

    Science.gov (United States)

    Chandran, Suresh R; Balakrishnan, Rojith K; Umakanthan, K; Govindarajan, K

    2012-01-01

    Neurocysticercosis is a common tropical infection presenting with neurological signs. It commonly presents as seizures but various other focal neurological presentations have been reported. Though neurocysticercosis have been reported to present as isolated internuclear ophthalmoplegia, we report the first case of neurocysticercosis presenting as wall-eyed monoocular internuclear ophthalmoplegia syndrome with contraversive ocular tilt reaction.

  9. Neurocysticercosis presenting as isolated wall-eyed monocular internuclear ophthalmoplegia with contraversive ocular tilt reaction

    Directory of Open Access Journals (Sweden)

    Suresh R Chandran

    2012-01-01

    Full Text Available Neurocysticercosis is a common tropical infection presenting with neurological signs. It commonly presents as seizures but various other focal neurological presentations have been reported. Though neurocysticercosis have been reported to present as isolated internuclear ophthalmoplegia, we report the first case of neurocysticercosis presenting as wall-eyed monoocular internuclear ophthalmoplegia syndrome with contraversive ocular tilt reaction.

  10. Production and transport chemistry of atomic fluorine in remote plasma source and cylindrical reaction chamber

    International Nuclear Information System (INIS)

    Gangoli, S P; Johnson, A D; Fridman, A A; Pearce, R V; Gutsol, A F; Dolgopolsky, A

    2007-01-01

    Increasingly, NF 3 -based plasmas are being used in semiconductor manufacturing to clean chemical vapour deposition (CVD) chambers. With advantages such as faster clean times, substantially lower emissions of gases having high global warming potentials, and reduced chamber damage, NF 3 plasmas are now favoured over fluorocarbon-based processes. Typically, a remote plasma source (RPS) is used to dissociate the NF 3 gas and produce atomic fluorine that etches the CVD residues from the chamber surfaces. However, it is important to efficiently transport F atoms from the plasma source into the process chamber. The current work is aimed at understanding and improving the key processes involved in the production and transport of atomic fluorine atoms. A zero-dimensional model of NF 3 dissociation and F production chemistry in the RPS is developed based on various known and derived plasma parameters. Additionally, a model describing the transport of atomic fluorine is proposed that includes both physical (diffusion, adsorption and desorption) and chemical processes (surface and three-body volume recombination). The kinetic model provides an understanding of the impact of chamber geometry, gas flow rates, pressure and temperature on fluorine recombination. The plasma-kinetic model is validated by comparing model predictions (percentage F atom density) with experimental results (etch rates)

  11. Simulations of fusion chamber dynamics and first wall response in a Z-pinch driven fusion–fission hybrid power reactor (Z-FFR)

    Energy Technology Data Exchange (ETDEWEB)

    Qi, J.M., E-mail: qjm06@sina.com [Laboratory of Advanced Nuclear Energy (LANE), Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Center for Fusion Energy Science and Technology (CFEST), China Academy of Engineering Physics, Mianyang 621999 (China); Wang, Z., E-mail: wangz_es@caep.cn [Laboratory of Advanced Nuclear Energy (LANE), Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Center for Fusion Energy Science and Technology (CFEST), China Academy of Engineering Physics, Mianyang 621999 (China); Chu, Y.Y., E-mail: chuyanyun@caep.cn [Laboratory of Advanced Nuclear Energy (LANE), Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Center for Fusion Energy Science and Technology (CFEST), China Academy of Engineering Physics, Mianyang 621999 (China); Li, Z.H., E-mail: lee_march@sina.com [Laboratory of Advanced Nuclear Energy (LANE), Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China)

    2016-03-15

    Highlights: • Z-FFR utilizes DT neutrons to drive a sub-critical fission blanket to produce energy. • A metal shell and Ar gas are employed in the fusion chamber for shock mitigation. • Massive materials can effectively mitigate the thermal heats on the chamber wall. • The W-coated Zr-alloy first wall exhibits good viability as a long-lived component. - Abstract: In a Z-pinch driven fusion–fission hybrid power reactor (Z-FFR), the fusion target will produce enormous energy of ∼1.5 GJ per pulse at a frequency of 0.1 Hz. Almost 20% of the fusion energy yield, approximately 300 MJ, is released in forms of pulsed X-rays. To prevent the first wall from fatal damages by the intense X-rays, a thin spherical metal shell and rare Ar buffer gas are introduced to mitigate the transient X-ray bursts. Radiation hydrodynamics in the fusion chamber were investigated by MULTI-1D simulations, and the corresponding thermal and mechanical loads on the first wall were also obtained. The simulations indicated that by optimizing the design parameters of the metal shell and Ar buffer gas, peak power flux of the thermal heats on the first wall could be mitigated to less than 10{sup 4} W/cm{sup 2} within a time scale of several milliseconds, while peak overpressures of the mechanical loads varying from 0.6 to 0.7 MPa. In addition, the thermomechanical response in a W–coated Zr-alloy first wall was performed by FWDR1D calculations using the derived thermal and mechanical loads as inputs. The temperature and stress fields were analyzed, and the corresponding elastic strains were conducted for primary lifetime estimations by using the Coffin–Manson relationships of both W and Zr-alloy. It was shown that the maximum temperature rises and stresses in the first wall were less than 50 K and 130 MPa respectively, and lifetime of the first wall would be in excess of 10{sup 9} cycles. The chamber exhibits good viability as a long-lived component to sustain the Z-FFR conceptual

  12. Gas phase formation of extremely oxidized pinene reaction products in chamber and ambient air

    Directory of Open Access Journals (Sweden)

    M. Ehn

    2012-06-01

    Full Text Available High molecular weight (300–650 Da naturally charged negative ions have previously been observed at a boreal forest site in Hyytiälä, Finland. The long-term measurements conducted in this work showed that these ions are observed practically every night between spring and autumn in Hyytiälä. The ambient mass spectral patterns could be reproduced in striking detail during additional measurements of α-pinene (C10H16 oxidation at low-OH conditions in the Jülich Plant Atmosphere Chamber (JPAC. The ions were identified as clusters of the nitrate ion (NO3 and α-pinene oxidation products reaching oxygen to carbon ratios of 0.7–1.3, while retaining most of the initial ten carbon atoms. Attributing the ions to clusters instead of single molecules was based on additional observations of the same extremely oxidized organics in clusters with HSO4 (Hyytiälä and C3F5O2 (JPAC. The most abundant products in the ion spectra were identified as C10H14O7, C10H14O9, C10H16O9, and C10H14O11. The mechanism responsible for forming these molecules is still not clear, but the initial reaction is most likely ozone attack at the double bond, as the ions are mainly observed under dark conditions. β-pinene also formed highly oxidized products under the same conditions, but less efficiently, and mainly C9 compounds which were not observed in Hyytiälä, where β-pinene on average is 4–5 times less abundant than α-pinene. Further, to explain the high O/C together with the relatively high H/C, we propose that geminal diols and/or hydroperoxide groups may be important. We estimate that the night-time concentration of the sum of the neutral extremely oxidized products is on the order of 0.1–1 ppt (~10

  13. Chemical reactions inside the plasma chamber of the SEAFP reactor plant models

    International Nuclear Information System (INIS)

    Gay, J.M.; Ebert, E.; Mazille, F.

    1995-01-01

    Loss of coolant or loss of vacuum accidents may lead to chemical reactions between the protecting materials of the plasma facing components and air or water. A production of energy, reaction products and hydrogen may be induced. The paper defines the operating conditions and chemical reactions and presents the main results from the underlying studies. (orig.)

  14. A proposed community reaction-wall facility at the JRC Ispra

    Energy Technology Data Exchange (ETDEWEB)

    Jones, P M; Donea, J [Commission of the European Communities, Joint Research Centre - Ispra Establishment Applied Mechanics Division, Ispra (Italy)

    1988-07-01

    The paper describes a large-size structural laboratory based on a reaction-wall facility proposed for the JRC Ispra establishment. It is foreseen that this will be used for large and full-scale testing of a wide variety of structures and components in the fields of civil/structural, mechanical, and geotechnical engineering. After briefly reviewing the background market research done to establish the needs for a large central facility in the Community, the main advantages and limitations of reaction-wall testing in comparison with other experimental techniques are summarized. The main characteristics of the proposed facility are then given followed by the identified fields of research in which significant tests can be performed. Finally, the proposed method of implementing an integral programme of work within the European Community member states is presented. (author)

  15. A proposed community reaction-wall facility at the JRC Ispra

    International Nuclear Information System (INIS)

    Jones, P.M.; Donea, J.

    1988-01-01

    The paper describes a large-size structural laboratory based on a reaction-wall facility proposed for the JRC Ispra establishment. It is foreseen that this will be used for large and full-scale testing of a wide variety of structures and components in the fields of civil/structural, mechanical, and geotechnical engineering. After briefly reviewing the background market research done to establish the needs for a large central facility in the Community, the main advantages and limitations of reaction-wall testing in comparison with other experimental techniques are summarized. The main characteristics of the proposed facility are then given followed by the identified fields of research in which significant tests can be performed. Finally, the proposed method of implementing an integral programme of work within the European Community member states is presented. (author)

  16. The Magma Chamber Simulator: Modeling the Impact of Wall Rock Composition on Mafic Magmas during Assimilation-Fractional Crystallization

    Science.gov (United States)

    Creamer, J. B.; Spera, F. J.; Bohrson, W. A.; Ghiorso, M. S.

    2012-12-01

    Although stoichiometric titration is often used to model the process of concurrent Assimilation and Fractional Crystallization (AFC) within a compositionally evolving magma body, a more complete treatment of the problem involves simultaneous and self-consistent determination of stable phase relationships and separately evolving temperatures of both Magma (M) and Wall Rock (WR) that interact as a composite M-WR system. Here we present results of M-WR systems undergoing AFC forward modeled with the Magma Chamber Simulator (MCS), which uses the phase modeling capabilities of MELTS (Ghiorso & Sack 1995) as the thermodynamic basis. Simulations begin with one of a variety of mafic magmas (e.g. HAB, MORB, AOB) intruding a set mass of Wall Rock (e.g. lherzolite, gabbro, diorite, granite, metapelite), and heat is exchanged as the M-WR system proceeds towards thermal equilibrium. Depending on initial conditions, the early part of the evolution can involve closed system FC while the WR heats up. The WR behaves as a closed system until it is heated beyond the solidus to critical limit for melt fraction extraction (fc), ranging between 0.08 and 0.12 depending on WR characteristics including composition and, rheology and stress field. Once fc is exceeded, a portion of the anatectic liquid is assimilated into the Magma. The MCS simultaneously calculates mass and composition of the mineral assemblage (Magma cumulates and WR residue) and melt (anatectic and Magma) at each T along the equilibration trajectory. Sensible and latent heat lost or gained plus mass gained by the Magma are accounted for by the MCS via governing Energy Constrained- Recharge Assimilation Fractional Crystallization (EC-RAFC) equations. In a comparison of two representative MCS results, consider a granitic WR intruded by HAB melt (51 wt. % SiO2) at liquidus T in shallow crust (0.1 GPa) with a WR/M ratio of 1.25, fc of 0.1 and a QFM oxygen buffer. In the first example, the WR begins at a temperature of 100o

  17. Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

    CERN Document Server

    2016-01-01

    Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

  18. Experimental determination of temperatures of the inner wall of a boiler combustion chamber for the purpose of verification of a CFD model

    Directory of Open Access Journals (Sweden)

    Petr Trávníček

    2011-01-01

    Full Text Available The paper focuses on the non-destructive method of determination of temperatures in the boiler combustion chamber. This method proves to be significant mainly as regards CFD (Computational Fluid Dynamics simulations of combustion processes, in case of which it is subsequently advisable to verify the data calculated using CFD software application with the actually measured data. Verification of the method was based on usage of reference combustion equipment (130 kW which performs combustion of a mixture of waste sawdust and shavings originating in the course of production of wooden furniture. Measuring of temperatures inside the combustion chamber is – considering mainly the high temperature values – highly demanding and requires a special type of temperature sensors. Furthermore, as regards standard operation, it is not possible to install such sensors without performing structural alterations of the boiler. Therefore, for the purpose of determination of these temperatures a special experimental device was constructed while exploiting a thermal imaging system used for monitoring of the surface temperature of outer wall of the reference boiler. Temperatures on the wall of the boiler combustion chamber were determined on the basis of data measured using the experimental device as well as data from the thermal imaging system. These values might serve for verification of the respective CFD model of combustion equipment.

  19. Study of (α , p) and (α , n) reactions with a Multi-Sampling Ionization Chamber

    Science.gov (United States)

    Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; Ayangeakaa, A. D.; Dickerson, C.; Hoffman, C. R.; Jiang, C. L.; Kay, B. P.; Lai, J.; Nusair, O.; Pardo, R. C.; Santiago-Gonzalez, D.; Talwar, R.; Ugalde, C.

    2017-07-01

    A large number of (α , p) and (α , n) reactions are known to play a fundamental role in nuclear astrophysics. This work presents a novel technique to study these reactions with the active target system MUSIC whose segmented anode allows the investigation of a large energy range of the excitation function with a single beam energy. In order to verify the method, we performed direct measurements of the previously measured reactions 17O (α , n) 20Ne, 23Na (α , p) 26Mg, and 23Na (α , n) 26Al. These reactions were investigated in inverse kinematics using 4He gas in the detector to study the excitation functions in the energy range of about 2-6 MeV in the center of mass. We found good agreement between the cross sections of the 17O (α , n) 20Ne reaction measured in this work and previous measurements. Furthermore we have successfully performed a simultaneous measurement of the 23Na (α , p) 26Mg and 23Na (α , n) 26Al reactions.

  20. Evaluating the impact of new observational constraints on P-S/IVOC emissions, multi-generation oxidation, and chamber wall losses on SOA modeling for Los Angeles, CA

    Science.gov (United States)

    Ma, Prettiny K.; Zhao, Yunliang; Robinson, Allen L.; Worton, David R.; Goldstein, Allen H.; Ortega, Amber M.; Jimenez, Jose L.; Zotter, Peter; Prévôt, André S. H.; Szidat, Sönke; Hayes, Patrick L.

    2017-08-01

    Secondary organic aerosol (SOA) is an important contributor to fine particulate matter (PM) mass in polluted regions, and its modeling remains poorly constrained. A box model is developed that uses recently published literature parameterizations and data sets to better constrain and evaluate the formation pathways and precursors of urban SOA during the CalNex 2010 campaign in Los Angeles. When using the measurements of intermediate-volatility organic compounds (IVOCs) reported in Zhao et al. (2014) and of semi-volatile organic compounds (SVOCs) reported in Worton et al. (2014) the model is biased high at longer photochemical ages, whereas at shorter photochemical ages it is biased low, if the yields for VOC oxidation are not updated. The parameterizations using an updated version of the yields, which takes into account the effect of gas-phase wall losses in environmental chambers, show model-measurement agreement at longer photochemical ages, even though some low bias at short photochemical ages still remains. Furthermore, the fossil and non-fossil carbon split of urban SOA simulated by the model is consistent with measurements at the Pasadena ground site. Multi-generation oxidation mechanisms are often employed in SOA models to increase the SOA yields derived from environmental chamber experiments in order to obtain better model-measurement agreement. However, there are many uncertainties associated with these aging mechanisms. Thus, SOA formation in the model is compared to data from an oxidation flow reactor (OFR) in order to constrain SOA formation at longer photochemical ages than observed in urban air. The model predicts similar SOA mass at short to moderate photochemical ages when the aging mechanisms or the updated version of the yields for VOC oxidation are implemented. The latter case has SOA formation rates that are more consistent with observations from the OFR though. Aging mechanisms may still play an important role in SOA chemistry, but the

  1. Analysis of the energy transport and deposition within the reaction chamber of the Prometheus inertial fusion energy reactor

    International Nuclear Information System (INIS)

    Eggleston, J.E.; Abdou, M.A.; Tillack, M.S.

    1995-01-01

    The thermodynamic response of the Prometheus reactor chamber was analyzed and, from this analysis, a simplified thermodynamic response model was developed for parametric studies on this conceptual reactor design. This paper discusses the thermodynamic response of the cavity gas and models the condensation/evaporation of vapor to and from the first wall. Models of X-ray attenuation and ion slowing down are used to estimate the fraction of the pellet energy that is absorbed in the vapor. It was found that the gas absorbs enough energy to become partially ionized. To treat this problem, methods developed by Zel'dovich and Raizer are used in modeling the internal energy and the radiative heat flux of the vapor.From this analysis, RECON was developed, which runs with a relatively short computational time, yet retains enough accuracy for conceptual reactor design calculations. The code was used to determine whether the reactor designs could meet the stringent mass density limits that are placed on them by the physics of beam propagation through matter. RECON was also used to study the effect that the formation of a local dry spot would have on the first wall of the reactor. It was found that, for a typical reactor lifetime of 30 years, the first wall could not have a dry spot over any one section for more than 15.5 min for the laser driver design and 4.5 min for the heavy ion driver design. These times are relatively short, which implies that there is a need to keep the liquid film attached at all times. (orig.)

  2. Dynamic thermal reaction analysis of wall structures in various cooling operation conditions

    International Nuclear Information System (INIS)

    Yan, Biao; Long, Enshen; Meng, Xi

    2015-01-01

    Highlights: • Four different envelop structures are separately built in the same test building. • Cooling temperature and operation time were chosen as perturbations. • State Space Method is used to analyze the influence of wall sequence order. • The numerical models are validated by the comparisons of theory and test results. • The contrast of temperature change of different envelop structures was stark. - Abstract: This paper proposes a methodology of performance assessing of envelops under different cooling operation conditions, by focusing on indoor temperature change and dynamic thermal behavior performance of walls. To obtain a general relationship between the thermal environment change and the reaction of envelop, variously insulated walls made with the same insulation material are separately built in the same wall of a testing building with the four different structures, namely self-heat insulation (full insulation material), exterior insulation, internal insulation and intermediate insulation. The advantage of this setting is that the test targets are exposed to the same environmental variables, and the tests results are thus comparable. The target responses to two types of perturbations, cooling temperature and operation time were chosen as the important variations in the tests. Parameters of cooling set temperature of 22 °C and 18 °C, operation and restoring time 10 min and 15 min are set in the test models, and discussed with simulation results respectively. The results reveal that the exterior insulation and internal insulation are more sensitive to thermal environment change than self-heat insulation and intermediate insulation.

  3. Calculation of reaction forces in the boiler supports using the method of equivalent stiffness of membrane wall.

    Science.gov (United States)

    Sertić, Josip; Kozak, Dražan; Samardžić, Ivan

    2014-01-01

    The values of reaction forces in the boiler supports are the basis for the dimensioning of bearing steel structure of steam boiler. In this paper, the application of the method of equivalent stiffness of membrane wall is proposed for the calculation of reaction forces. The method of equalizing displacement, as the method of homogenization of membrane wall stiffness, was applied. On the example of "Milano" boiler, using the finite element method, the calculation of reactions in the supports for the real geometry discretized by the shell finite element was made. The second calculation was performed with the assumption of ideal stiffness of membrane walls and the third using the method of equivalent stiffness of membrane wall. In the third case, the membrane walls are approximated by the equivalent orthotropic plate. The approximation of membrane wall stiffness is achieved using the elasticity matrix of equivalent orthotropic plate at the level of finite element. The obtained results were compared, and the advantages of using the method of equivalent stiffness of membrane wall for the calculation of reactions in the boiler supports were emphasized.

  4. Calculation of Reaction Forces in the Boiler Supports Using the Method of Equivalent Stiffness of Membrane Wall

    Directory of Open Access Journals (Sweden)

    Josip Sertić

    2014-01-01

    Full Text Available The values of reaction forces in the boiler supports are the basis for the dimensioning of bearing steel structure of steam boiler. In this paper, the application of the method of equivalent stiffness of membrane wall is proposed for the calculation of reaction forces. The method of equalizing displacement, as the method of homogenization of membrane wall stiffness, was applied. On the example of “Milano” boiler, using the finite element method, the calculation of reactions in the supports for the real geometry discretized by the shell finite element was made. The second calculation was performed with the assumption of ideal stiffness of membrane walls and the third using the method of equivalent stiffness of membrane wall. In the third case, the membrane walls are approximated by the equivalent orthotropic plate. The approximation of membrane wall stiffness is achieved using the elasticity matrix of equivalent orthotropic plate at the level of finite element. The obtained results were compared, and the advantages of using the method of equivalent stiffness of membrane wall for the calculation of reactions in the boiler supports were emphasized.

  5. A combined plant and reaction chamber setup to investigate the effect of pollution and UV-B radiation on biogenic emissions

    Science.gov (United States)

    Timkovsky, J.; Gankema, P.; Pierik, R.; Holzinger, R.

    2012-12-01

    Biogenic emissions account for almost 90% of total non-methane organic carbon emissions in the atmosphere. The goal of this project is to study the effect of pollution (ozone, NOx) and UV radiation on the emission of real plants. We have designed and built a setup where we combine plant chambers with a reaction chamber (75L volume) allowing the addition of pollutants at different locations. The main analytical tool is a PTR-TOF-MS instrument that can be optionally coupled with a GC system for improved compound identification. The setup is operational since March 2012 and first measurements indicate interesting results, three types of experiments will be presented: 1. Ozonolysis of b-pinene. In this experiment the reaction chamber was flushed with air containing b-pinene at approximate levels of 50 nmol/mol. After ~40 min b-pinene levels reached equilibrium in the reaction chamber and a constant supply of ozone was provided. Within 30 minutes this resulted in a 10 nmol/mol decrease of b-pinene levels in accordance with a reaction rate constant of 1.5*10-17 cm3molec-1s-1 and a residence time of 10 minutes in the reaction chamber. In addition we observed known oxidation products such as formaldehyde, acetone, and nopinone the molar yields of which were also in accordance with reported values. 2. Ozonolysis of biogenic emissions from tomato plants. The air containing the emissions from tomato plants was supplied to the reaction chamber. After adding ozone we observed the decrease of monoterpene concentrations inside the reaction chamber. The observed decrease is consistent for online PTR-MS and GC/PTR-MS measurements. Several ozonolysis products have been observed in the chamber. 3. The effect of UV-B radiation on biogenic emissions of tomato plants. Tomato plants were exposed to UV-B radiation and their emissions measured during and after the treatment. We observed significant changes in the emissions of volatile organic compounds, with specific compounds increasing

  6. Laser damage study of material of the first wall of target chamber of the future laser Megajoule

    International Nuclear Information System (INIS)

    Dubern, Christelle

    1999-01-01

    Study on damage of carbon-like, boron carbide, and stainless steel materials by ultraviolet laser light, has been carried out at CEA/CESTA in France. This work was performed to help designing and dimensioning the target chamber of the future Laser MegaJoule (LMJ) facility to be used for Inertial Confinement Fusion research. The study revealed that depending the laser fluence, the considered materials were ablated in different manners. lt was demonstrated that at low fluence, damage of carbon-like and boron carbide occurs through a thermal-mechanical mechanism resulting in sputtering of material. At higher fluence, damage was driven by a thermal mechanism, dissipating heat inside material until phase change developed. For stainless steel material, failures were the result of heat absorption associated to physical changes only. To explain and validate the proposed mechanisms, theoretical and experimental works were performed and satisfactory results came out. (author) [fr

  7. KOH-activated multi-walled carbon nanotubes as platinum supports for oxygen reduction reaction

    Science.gov (United States)

    He, Chaoxiong; Song, Shuqin; Liu, Jinchao; Maragou, Vasiliki; Tsiakaras, Panagiotis

    In the present investigation, multi-walled carbon nanotubes (MWCNTs) thermally treated by KOH were adopted as the platinum supporting material for the oxygen reduction reaction electrocatalysts. FTIR and Raman spectra were used to investigate the surface state of MWCNTs treated by KOH at different temperatures (700, 800, and 900 °C) and showed MWCNTs can be successfully functionalized. The structural properties of KOH-activated MWCNTs supported Pt were determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their electrochemical performance was evaluated by the aid of cyclic voltammetry (CV) and rotating disk electrode (RDE) voltammetry. According to the experimental findings of the present work, the surrface of MWCNTs can be successfully functionalized with oxygen-containing groups after activation by KOH, favoring the good dispersion of Pt nanoparticles with narrow size distribution. The as-prepared Pt catalysts supported on KOH treated MWCNTs at higher temperature, possess higher electrochemical surface area and exhibit desirable activity towards oxygen reduction reaction (ORR). More precisely, it has been found that the electrochemical active area of Pt/MWCNTs-900 is approximately two times higher than that of Pt/MWCNTs. It can be concluded that KOH activation is an effective way to decorate MWCNTs' surface with oxygen-containing groups and bigger surface area, which makes them more suitable as electrocatalyst support materials.

  8. Compositional change of some first wall materials by considering multiple step nuclear reaction

    Energy Technology Data Exchange (ETDEWEB)

    Noda, Tetsuji; Utsumi, Misako; Fujita, Mitsutane [National Research Inst. for Metals, Tsukuba, Ibaraki (Japan)

    1997-03-01

    The conceptual system for nuclear material design is considered and some trials on WWW server with functions of the easily accessible simulation of nuclear reactions are introduced. Moreover, as an example of the simulation on the system using nuclear data, transmutation calculation was made for candidate first wall materials such as 9Cr-2W steel, V-5Cr-5Ti and SiC in SUS316/Li{sub 2}O/H{sub 2}O(SUS), 9Cr-2WLi{sub 2}O/H{sub 2}O(RAF), V alloy/Li/Be(V), and SiC/Li{sub 2}ZrO{sub 3}/He(SiC) blanket/shield systems based on ITER design model. Neutron spectrum varies with different blanket/shield compositions. The flux of low energy neutrons decreases in order of V-SiC-RAF-SUS blanket/shield systems. Fair amounts of W depletion in 9Cr-2W steel and the increase of Cr content in V-5Cr-5Ti were predicted in SUS or RAF systems. Concentration change in W and Cr is estimated to be suppressed if Li coolant is used in place of water. Helium and hydrogen production are not strongly affected by the different blanket/shield compositions. (author)

  9. The construction and operating characteristics of a cathode strip chamber system designed to measure the reaction vertices of a stopping kaon beam

    International Nuclear Information System (INIS)

    M.W. Ahmed; D. Androic; I. Bertovic; J. Bjoraker; R. Chrien; X. Cui; D. Dehnhard; Anton Empl; M. Furic; J. Gerald; R. Gill; E.V. Hungerford; H. Jungst; K.J. Lan; Jinghua Liu; C.L. Morris; J.M. O'Donnell; J.C. Peng; T. Petkovic; P. Pile; M. Planinic; C.M. Riedel; A. Rusek; R. Sutter; Liguang Tang; H.A. Thiessen; M. Youn; V. Zeps

    2001-01-01

    The design, construction, and performance of a segmented-target, cathode-strip, tracking-detector is discussed. The chamber was made of low-Z materials in order to allow photons to leave the target region. It was used to determine the reaction vertex of stopping kaons, and was successfully operated in a high-intensity kaon beamline at the Alternating Gradient Synchrotron at Brookhaven National Laboratory. The vertical and horizontal resolutions of the stopping kaon reaction positions were sigma X∼ 0.454mm and sigma Y∼ 1.180mm, respectively. The uncertainty in the longitudinal (Z) direction is given by one-half the thickness of a target segment

  10. Method and apparatus for obtaining enhanced production rate of thermal chemical reactions

    Science.gov (United States)

    Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Wegeng, Robert S [Richland, WA; Gao, Yufei [Kennewick, WA

    2003-04-01

    The present invention is a method and apparatus (vessel) for providing a heat transfer rate from a reaction chamber through a wall to a heat transfer chamber substantially matching a local heat transfer rate of a catalytic thermal chemical reaction. The key to the invention is a thermal distance defined on a cross sectional plane through the vessel inclusive of a heat transfer chamber, reaction chamber and a wall between the chambers. The cross sectional plane is perpendicular to a bulk flow direction of the reactant stream, and the thermal distance is a distance between a coolest position and a hottest position on the cross sectional plane. The thermal distance is of a length wherein the heat transfer rate from the reaction chamber to the heat transfer chamber substantially matches the local heat transfer rate.

  11. Reactivity of Single-Walled Carbon Nanotubes in the Diels-Alder Cycloaddition Reaction: Distortion-Interaction Analysis along the Reaction Pathway.

    Science.gov (United States)

    Li, Yingzi; Osuna, Sílvia; Garcia-Borràs, Marc; Qi, Xiaotian; Liu, Song; Houk, Kendall N; Lan, Yu

    2016-08-26

    Diels-Alder cycloaddition is one of the most powerful tools for the functionalization of single-walled carbon nanotubes (SWCNTs). Density functional theory at the B3-LYP level of theory has been used to investigate the reactivity of different-diameter SWCNTs (4-9,5) in Diels-Alder reactions with 1,3-butadiene; the reactivity was found to decrease with increasing SWCNT diameter. Distortion/interaction analysis along the whole reaction pathway was found to be a better way to explore the reactivity of this type of reaction. The difference in interaction energy along the reaction pathway is larger than that of the corresponding distortion energy. However, the distortion energy plots for these reactions show the same trend. Therefore, the formation of the transition state can be determined from the interaction energy. A lower interaction energy leads to an earlier transition state, which indicates a lower activation energy. The computational results also indicate that the original distortion of the SWCNTs leads to an increase in the reactivity of the SWCNTs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. The construction and operating characteristics of a cathode strip chamber system designed to measure the reaction vertices of a stopping kaon beam

    International Nuclear Information System (INIS)

    Ahmed, M.W.; Androic, D.; Bertovic, I.; Bjoraker, J.; Chrien, R.; Cui, X.; Dehnhard, D.; Empl, A.; Furic, M.; Gerald, J.; Gill, R.; Hungerford, E.V.; Juengst, H.; Lan, K.J.; Liu, J.H.; Morris, C.L.; O'Donnell, J.M.; Peng, J.C.; Petkovic, T.; Pile, P.; Planinic, M.; Riedel, C.M.; Rusek, A.; Sutter, R.; Tang, L.; Thiessen, H.A.; Youn, M.; Zeps, V.

    2001-01-01

    The design, construction, and performance of a segmented-target, cathode-strip, tracking-detector is discussed. The chamber was made of low-Z materials in order to allow photons to leave the target region. It was used to determine the reaction vertex of stopping kaons, and was successfully operated in a high-intensity kaon beamline at the Alternating Gradient Synchrotron at Brookhaven National Laboratory. The vertical and horizontal resolutions of the stopping kaon reaction positions were σ X ∼0.454 mm and σ Y ∼1.180 mm, respectively. The uncertainty in the longitudinal (Z) direction is given by one-half the thickness of a target segment

  13. The construction and operating characteristics of a cathode strip chamber system designed to measure the reaction vertices of a stopping kaon beam

    CERN Document Server

    Ahmed, M W; Bertovic, I; Bjoraker, J; Chrien, R; Cui, X; Dehnhard, D; Empl, A; Furic, M; Gerald, J; Gill, R; Hungerford, E V; Juengst, H; Lan, K J; Liu, J H; Morris, C L; O'donnell, J M; Peng, J C; Petkovic, T; Pile, P; Planinic, M; Riedel, C M; Rusek, A; Sutter, R; Tang, L; Thiessen, H A; Youn, M; Zeps, V

    2001-01-01

    The design, construction, and performance of a segmented-target, cathode-strip, tracking-detector is discussed. The chamber was made of low-Z materials in order to allow photons to leave the target region. It was used to determine the reaction vertex of stopping kaons, and was successfully operated in a high-intensity kaon beamline at the Alternating Gradient Synchrotron at Brookhaven National Laboratory. The vertical and horizontal resolutions of the stopping kaon reaction positions were sigma sub X approx 0.454 mm and sigma sub Y approx 1.180 mm, respectively. The uncertainty in the longitudinal (Z) direction is given by one-half the thickness of a target segment.

  14. Studies on the heterogeneous electron transport and oxygen reduction reaction at metal (Co, Fe) octabutylsulphonylphthalocyanines supported on multi-walled carbon nanotube modified graphite electrode

    CSIR Research Space (South Africa)

    Mamuru, SA

    2010-09-01

    Full Text Available Heterogeneous electron transfer dynamics and oxygen reduction reaction (ORR) activities using octabutylsulphonylphthalocyanine complexes of iron (FeOBSPc) and cobalt (CoOBSPc) supported on multi-walled carbon nanotube (MWCNT) platforms have been...

  15. Iron (II) tetrakis(diaquaplatinum) octacarboxyphthalocyanine supported on multi-walled carbon nanotubes as effective electrocatalyst for oxygen reduction reaction in alkaline medium

    CSIR Research Space (South Africa)

    Mamuru, SA

    2010-11-01

    Full Text Available Oxygen reduction reaction (ORR) in alkaline medium at iron (II) tetrakis (diaquaplatinum) octacarboxyphthalocyanine (PtFeOCPc) catalyst supported on multi-walled carbon nanotubes (MWCNTs) has been described. The ORR followed the direct 4-electron...

  16. Study of (α,p) and (α,n) reactions with a Multi-Sampling Ionization Chamber

    International Nuclear Information System (INIS)

    Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; Ayangeakaa, A. D.; Dickerson, C.

    2017-01-01

    Here, a large number of (α,p) and (α, n) reactions are known to play a fundamental role in nuclear astrophysics. This work presents a novel technique to study these reactions with the active target system MUSIC whose segmented anode allows the investigation of a large energy range of the excitation function with a single beam energy. In order to verify the method, we performed direct measurements of the previously measured reactions "1"7O (α, n) "2"0Ne, "2"3Na (α,p) "2"6Mg, and "2"3Na "2"6Al. These reactions were investigated in inverse kinematics using "4He gas in the detector to study the excitation functions in the energy range of about 2–6 MeV in the center of mass. We found good agreement between the cross sections of the "1"7O (α, n) "2"0Ne reaction measured in this work and previous measurements. Furthermore we have successfully performed a simultaneous measurement of the "2"3Na (α,p) "2"6Mg and "2"3Na (α, n) "2"6Al reactions.

  17. Role of adsorbed surfactant in the reaction of aryl diazonium salts with single-walled carbon nanotubes.

    Science.gov (United States)

    Hilmer, Andrew J; McNicholas, Thomas P; Lin, Shangchao; Zhang, Jingqing; Wang, Qing Hua; Mendenhall, Jonathan D; Song, Changsik; Heller, Daniel A; Barone, Paul W; Blankschtein, Daniel; Strano, Michael S

    2012-01-17

    Because covalent chemistry can diminish the optical and electronic properties of single-walled carbon nanotubes (SWCNTs), there is significant interest in developing methods of controllably functionalizing the nanotube sidewall. To date, most attempts at obtaining such control have focused on reaction stoichiometry or strength of oxidative treatment. Here, we examine the role of surfactants in the chemical modification of single-walled carbon nanotubes with aryl diazonium salts. The adsorbed surfactant layer is shown to affect the diazonium derivatization of carbon nanotubes in several ways, including electrostatic attraction or repulsion, steric exclusion, and direct chemical modification of the diazonium reactant. Electrostatic effects are most pronounced in the cases of anionic sodium dodecyl sulfate and cationic cetyltrimethylammonium bromide, where differences in surfactant charge can significantly affect the ability of the diazonium ion to access the SWCNT surface. For bile salt surfactants, with the exception of sodium cholate, we find that the surfactant wraps tightly enough such that exclusion effects are dominant. Here, sodium taurocholate exhibits almost no reactivity under the explored reaction conditions, while for sodium deoxycholate and sodium taurodeoxycholate, we show that the greatest extent of reaction is observed among a small population of nanotube species, with diameters between 0.88 and 0.92 nm. The anomalous reaction of nanotubes in this diameter range seems to imply that the surfactant is less effective at coating these species, resulting in a reduced surface coverage on the nanotube. Contrary to the other bile salts studied, sodium cholate enables high selectivity toward metallic species and small band gap semiconductors, which is attributed to surfactant-diazonium coupling to form highly reactive diazoesters. Further, it is found that the rigidity of anionic surfactants can significantly influence the ability of the surfactant layer to

  18. Vacuum Chambers for LEP sections

    CERN Multimedia

    1983-01-01

    The picture shows sections of the LEP vacuum chambers to be installed in the dipole magnets (left) and in the quadrupoles (right). The dipole chamber has three channels: the beam chamber, the pumping duct where the NEG (non-evaporabe getter) is installed and the water channel for cooling (on top in the picture). The pumping duct is connected to the beam chamber through holes in the separating wall. The thick lead lining to shield radiation can also be seen. These chambers were manufactured as extruded aluminium alloy profiles.

  19. The reaction of lithium metal vapor with single walled carbon nanotubes of large diameters

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Kavan, Ladislav; Dunsch, L.

    2009-01-01

    Roč. 246, 11-12 (2009), s. 2428-2431 ISSN 0370-1972 R&D Projects: GA AV ČR IAA400400911; GA AV ČR KAN200100801; GA AV ČR IAA400400804; GA ČR GC203/07/J067; GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : lithium * single walled carbon nanotubes * Raman spectroscopy Subject RIV: CG - Electrochemistry Impact factor: 1.150, year: 2009

  20. Ion chamber instrument

    International Nuclear Information System (INIS)

    Stephan, D.H.

    1975-01-01

    An electrical ionization chamber is described having a self-supporting wall of cellular material which is of uniform areal density and formed of material, such as foamed polystyrene, having an average effective atomic number between about 4 and about 9, and easily replaceable when on the instrument. (auth)

  1. Ionization chamber

    International Nuclear Information System (INIS)

    Jilbert, P.H.

    1975-01-01

    The invention concerns ionization chambers with particular reference to air-equivalent ionization chambers. In order to ensure that similar chambers have similar sensitivities and responses the surface of the chamber bounding the active volume carries a conducting material, which may be a colloidal graphite, arranged in the form of lines so that the area of the conducting material occupies only a small proportion of the area of said surface. (U.S.)

  2. Near wall combustion modeling in spark ignition engines. Part B: Post-flame reactions

    International Nuclear Information System (INIS)

    Demesoukas, Sokratis; Caillol, Christian; Higelin, Pascal; Boiarciuc, Andrei; Floch, Alain

    2015-01-01

    Highlights: • Models for the post flame reactions (CO and hydrocarbons) and heat release rate are proposed. • ‘Freezing’ effect of CO kinetics is captured but equilibrium CO concentrations are low. • Reactive–diffusive processes are modeled for hydrocarbons and the last stage of combustion is captured. - Abstract: Reduced fuel consumption, low pollutant emissions and adequate output performance are key features in the contemporary design of spark ignition engines. Zero-dimensional numerical simulation is an attractive alternative to engine experiments for the evaluation of various engine configurations. Both flame front reaction and post-flame processes contribute to the heat release rate. The contribution of this work is to highlight and model the role of post-flame reactions (CO and hydrocarbons) in the heat release rate. The modeling approach to CO kinetics used two reactions considered to be dominant and thus more suitable for the description of CO chemical mechanism. Equilibrium concentrations of all the species involved were calculated by a two-zone thermodynamic model. The computed characteristic time of CO kinetics was found to be of a similar order to the results of complex chemistry simulations. The proposed model captured the ‘freezing’ effect (reaction rate is almost zero) for temperatures lower than 1800 K and followed the trends of the measured values at exhaust. However, a consistent underestimation of CO levels at the exhaust was observed. The impact of the remaining CO on the combustion efficiency is considerable especially for rich mixtures. For a remaining 0.4% CO mass fraction, the impact on combustion inefficiency is 0.1%. Unburnt hydrocarbon, which have not reacted within the flame front before quenching, diffuse in the burnt gas and react. In this work, a global reaction rate models the kinetic behavior of hydrocarbon. The diffusion process was modeled by a relaxation equation applied on the calculated kinetic concentration

  3. Test chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2009-01-01

    A test chamber for measuring electromagnetic radiation emitted by an apparatus to be tested or for exposing an apparatus to be tested to an electromagnetic radiation field. The test chamber includes a reverberation chamber made of a conductive tent fabric. To create a statistically uniform field in

  4. Conditioning of vacuum chamber by RF plasma

    International Nuclear Information System (INIS)

    Elizondo, J.I.; Nascimento, I.C. do

    1985-01-01

    A new conditioning vaccum chamber system is presented. It consists in hydrogen plasm generation by microwaves with low electronic temperature (Te approx. 5eV) and low ionization degree. The ions and neutral atoms generated in the reaction: e + H 2 -> H+ H+ e, bomb the chamber walls combinig themselves to impurities of surface and generating several compounds: H 2 O, CO, CH 4 , CO 2 etc. The vacuum system operates continuosly and remove these compounds. A microwave system using magnetron valve (f=2,45 GHz, P=800W) was constructed for TBR (Brazilian tokamak). The gas partial pressures were monitored before, during and after conditioning showing the efficiency of the process. (M.C.K.) [pt

  5. A global model for SF6 plasmas coupling reaction kinetics in the gas phase and on the surface of the reactor walls

    International Nuclear Information System (INIS)

    Kokkoris, George; Panagiotopoulos, Apostolos; Gogolides, Evangelos; Goodyear, Andy; Cooke, Mike

    2009-01-01

    Gas phase and reactor wall-surface kinetics are coupled in a global model for SF 6 plasmas. A complete set of gas phase and surface reactions is formulated. The rate coefficients of the electron impact reactions are based on pertinent cross section data from the literature, which are integrated over a Druyvesteyn electron energy distribution function. The rate coefficients of the surface reactions are adjustable parameters and are calculated by fitting the model to experimental data from an inductively coupled plasma reactor, i.e. F atom density and pressure change after the ignition of the discharge. The model predicts that SF 6 , F, F 2 and SF 4 are the dominant neutral species while SF 5 + and F - are the dominant ions. The fit sheds light on the interaction between the gas phase and the reactor walls. A loss mechanism for SF x radicals by deposition of a fluoro-sulfur film on the reactor walls is needed to predict the experimental data. It is found that there is a net production of SF 5 , F 2 and SF 6 , and a net consumption of F, SF 3 and SF 4 on the reactor walls. Surface reactions as well as reactions between neutral species in the gas phase are found to be important sources and sinks of the neutral species.

  6. Analysis of the reaction γp → J/ψp, J/ψ → μ+μ- with the help of the planar drift chambers of the ZEUS detector

    International Nuclear Information System (INIS)

    Coboeken, K.

    2000-03-01

    The software for track segment reconstruction in the forward planar drift chambers, FTD1-3, in the ZEUS experiment at the electron-proton storage ring HERA at DESY (Hamburg) has been improved and extended. A global forward track fit has been developed combining the segments in FTD1-3 with track segments in the central drift chamber and the forward muon chambers using Kalman filter techniques. Photoproduction events from the reaction ep→J/ψp, J/ψ→μ + μ - were studied. The reaction cross section as a function of the hadronic mass W in the range from 20 GeV to 130 GeV has been measured. The cross section for W between 20 and 30 GeV has been determined for the first time. This was only possible using the new developed forward track fit. This measurement fills the W gap between fixed target experiments and previous HERA measurements at higher values. (orig.)

  7. Impedances in lossy elliptical vacuum chambers

    International Nuclear Information System (INIS)

    Piwinski, A.

    1994-04-01

    The wake fields of a bunched beam caused by the resistivity of the chamber walls are investigated for a vacuum chamber with elliptical cross section. The longitudinal and transverse impedances are calculated for arbitrary energies and for an arbitrary position of the beam in the chamber. (orig.)

  8. Ussing Chamber

    NARCIS (Netherlands)

    Westerhout, J.; Wortelboer, H.; Verhoeckx, K.

    2015-01-01

    The Ussing chamber system is named after the Danish zoologist Hans Ussing, who invented the device in the 1950s to measure the short-circuit current as an indicator of net ion transport taking place across frog skin (Ussing and Zerahn, Acta Physiol Scand 23:110-127, 1951). Ussing chambers are

  9. wire chamber

    CERN Multimedia

    Proportional multi-wire chamber. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle. Proportional wire chambers allow a much quicker reading than the optical or magnetoscriptive readout wire chambers.

  10. Drift chamber

    International Nuclear Information System (INIS)

    Inagaki, Yosuke

    1977-01-01

    Drift chamber is becoming an important detector in high energy physics as a precision and fast position detector because of its high spatial resolution and count-rate. The basic principle is that it utilizes the drift at constant speed of electrons ionized along the tracks of charged particles towards the anode wire in the nearly uniform electric field. The method of measuring drift time includes the analog and digital ones. This report describes about the construction of and the application of electric field to the drift chamber, mathematical analysis on the electric field and equipotential curve, derivation of spatial resolution and the factor for its determination, and selection of gas to be used. The performance test of the chamber was carried out using a small test chamber, the collimated β source of Sr-90, and 500 MeV/C electron beam from the 1.3 GeV electron synchrotron in the Institute of Nuclear Study, University of Tokyo. Most chambers to date adopted one dimensional read-out, but it is very advantageous if the two dimensional read-out is feasible with one chamber when the resolution in that direction is low. The typical methods of delay line and charge division for two dimensional read-out are described. The development of digital read-out system is underway, which can process the signal of a large scale drift chamber at high speed. (Wakatsuki, Y.)

  11. Wire Chamber

    CERN Multimedia

    Magnetoscriptive readout wire chamber. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  12. Wire chamber

    CERN Multimedia

    1967-01-01

    Magnetoscriptive readout wire chamber.Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  13. Pencil-shaped radiation detection ionization chamber

    International Nuclear Information System (INIS)

    Suzuki, A.

    1979-01-01

    A radiation detection ionization chamber is described. It consists of an elongated cylindrical pencil-shaped tubing forming an outer wall of the chamber and a center electrode disposed along the major axis of the tubing. The length of the chamber is substantially greater than the diameter. A cable connecting portion at one end of the chamber is provided for connecting the chamber to a triaxial cable. An end support portion is connected at the other end of the chamber for supporting and tensioning the center electrode. 17 claims

  14. Ionization chamber

    International Nuclear Information System (INIS)

    1977-01-01

    An improved ionization chamber type X-ray detector comprises a heavy gas at high pressure disposed between an anode and a cathode. An open grid structure is placed next to the anode and is maintained at a voltage intermediate between the cathode and anode potentials. The electric field which is produced by positive ions drifting towards the cathode is thus shielded from the anode. Current measuring circuits connected to the anode are, therefore, responsive only to electron current flow within the chamber and the recovery time of the chamber is shortened. The grid structure also serves to shield the anode from electrical currents which might otherwise be induced by mechanical vibrations in the ionization chamber structure

  15. Ionization chambers

    International Nuclear Information System (INIS)

    Boag, J.W.

    1987-01-01

    Although a variety of solid-state and chemical methods for measuring radiation dose have been developed in recent decades and calorimetry can now provide an absolute standard of reference, ionization dosimetry retains its position as the most widely used, most convenient, and, in most situations, most accurate method of measuring either exposure or absorbed dose. The ionization chamber itself is the central element in this system of dosimetry. In this chapter the principles governing the construction and operation of ionization chambers of various types are examined. Since the ionization chambers now in general use are nearly all of commercial manufacture, the emphasis is on operating characteristics and interpretation of measurements rather than on details of construction, although some knowledge of the latter is often required when applying necessary corrections to the measured quantities. Examples are given of the construction of typical chambers designed for particular purposes, and the methods of calibrating them are discussed

  16. Determination of the correction factor for attenuation, dispersion and production of electrons (Kwall) in the wall of graphite of a ionization chamber Pattern National Type CC01 in fields of gamma radiation of 60Co

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Morales P, J.; Cruz E, P.

    2001-12-01

    It was determined the Kwall correction factor for the wall of graphite of the chamber of the pattern national type CC01 series 133 for a radiation field Gamma of 60 Co. With this end to measured the currents of ionization l(x) as function of the thickness of the wall of the chamber: X=4,8,12,16 and 20 mm.The mensurations for each thickness consisting of three groups, of sizes n = 30 or 60 data for each group; obtaining 8 complete groups of mensurations independent in eight different dates.The determinate the factor carried out using three regression models: lineal, logarithmic and quadratic, models that were tried to validate with the tests of : i) Shapiro-Wilk and χ 2 for the normality of the entrance data ii) Tests of Bartlett for variances homogeneity among groups for each thickness iii) The tests of Duncan for the stockings among groups of each thickness, and iv) The tests of adjustment lack (LOF) for the models used. Nevertheless, alone the models of the group of corresponding mensurations at 01-03-2000 17-08-2001 they can be validated by LOF, but not for tests of normality and homogeneity of variances. Among other assignable causes of variation we have: i) The values captured by the system of mensuration of the variables of it influences: pressure, temperature and relative humidity don t belong together with the existent ones to the moment to capture the l(x). ii) The mensuration room presents flows of air, for what was suited o diminish their volume and to eliminate the flows of air. iii) A protocol settled down of taking of measures that it consisted in: - Pre-irradiation 5 minutes the chamber after the change of polarity and hood change, with a period of stabilization of 5 minutes after the pre-irradiation. - Pre-irradiation for 5 minutes before the taking of the readings, with the object of eliminating variation sources assigned to currents of escapes or due variations to transitory. iv) To realize corrections for relative humidity of agreement with the

  17. Direct evidence for the origin of low-18O silicic magmas: Quenched samples of a magma chamber's partially-fused granitoid walls, Crater Lake, Oregon

    International Nuclear Information System (INIS)

    Bacon, C.R.; Adami, L.H.; Lanphere, M.A.

    1989-01-01

    Partially fused granitoid blocks were ejected in the climactic eruption of Mount Mazama, which was accompanied by collapse of Crater Lake caldera. Quartz, plagioclase, and glass in the granitoids have much lower δ 18 O values (-3.4 to +4.9per mille) than any fresh lavas of Mount Mazama and the surrounding region (+5.8 to +7.0per mille). Oxygen isotope fractionation between phases in granitoids is consistent with equilibrium at T≥900deg C following subsolidus exchange with hydrothermal fluids of meteoric origin. Assimilation of ≅ 10-20% of material similar to these granitoids can account for the O and Sr isotopic compositions of lavas and juvenile pyroclasts derived from the climactic magma chamber, many of which have δ 18 O values ≅ 0.5per mille or more lower than comparable lavas of Mount Mazama. The O isotope data provide the only clear evidence for such assimilation because the mineralogy and chemical and radiogenic isotopic compositions of the granitoids (dominantly granodiorite) are similar to those of erupted juvenile magmas. The granitoid blocks from Crater Lake serve as direct evidence for the origin of 18 O depletion in large, shallow silicic magma bodies. (orig.)

  18. Study of the heterogeneous reaction of O3 with CH3SCH3 using the wetted-wall flowtube technique

    Directory of Open Access Journals (Sweden)

    M. Barcellos da Rosa

    2003-01-01

    Full Text Available This work presents the heterogeneous kinetics of the reaction of CH3SCH3 (dimethyl sulphide, DMS with O3 (ozone in aqueous solutions of different ionic strengths (0, 0.1 and 1.0M NaCl using the wetted-wall flowtube (WWFT technique. Henry's law coefficients of DMS on pure water and on different concentrations of NaCl (0.1M - 4.0M in the WWFT from UV spectrophotometric measurements of DMS in the gas phase, using a numerical transport model of phase exchange, were determined to be H ±s (M atm-1 = 2.16±0.5 at 274.4 K, 1.47±0.3 at 283.4 K, 0.72±0.2 at 291 K, 0.57±0.1 at 303.4 K and 0.33±0.1 at 313.4 K on water, on 1.0M NaCl to be H = 1.57±0.4 at 275.7 K, 0.8±0.2 at 291 K and on 4.0M NaCl to be H = 0.44±0.1 at 275.7 K and 0.16±0.04 at 291 K, showing a significant effect of ionic strength, m, on the solubility of DMS according to the equation ln (H/M atm-1 = 4061 T-1 - 0.052 m2 - 50.9 m T-1 - 14.0. At concentrations of DMS(liq above 50 mM, UV spectrophotometry of both O3(gas and DMS(gas enables us to observe simultaneously the reactive uptake of O3 on DMS solution and the gas-liquid equilibration of DMS along the WWFT. The uptake coefficient, g (gamma, of O3 on aqueous solutions of DMS, varying between 1 and 15·10-6, showed a square root-dependence on the aqueous DMS concentration (as expected for diffusive penetration into the surface film, where the reaction takes place in aqueous solution. The uptake coefficient was smaller on NaCl solution in accord with the lower solubility of O3. The heterogeneous reaction of O3(gas with DMS(liq was evaluated from the observations of the second order rate constant (kII for the homogeneous aqueous reaction O3(liq + DMS(liq using a numerical model of radial diffusion and reactive penetration, leading to kII ± D kII (in units of 108 M-1 s-1 = 4.1±1.2 at 291.0 K, 2.15±0.65 at 283.4 K and 1.8±0.5 at 274.4 K. Aside from the expected influence on solubility and aqueous-phase diffusion coefficient of both

  19. Cloud Chamber

    DEFF Research Database (Denmark)

    Gfader, Verina

    Cloud Chamber takes its roots in a performance project, titled The Guests 做东, devised by Verina Gfader for the 11th Shanghai Biennale, ‘Why Not Ask Again: Arguments, Counter-arguments, and Stories’. Departing from the inclusion of the biennale audience to write a future folk tale, Cloud Chamber......: fiction and translation and translation through time; post literacy; world picturing-world typing; and cartographic entanglements and expressions of subjectivity; through the lens a social imaginary of worlding or cosmological quest. Art at its core? Contributions by Nikos Papastergiadis, Rebecca Carson...

  20. wire chamber

    CERN Multimedia

    1985-01-01

    Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  1. Wire chamber

    CERN Multimedia

    Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  2. wire chamber

    CERN Multimedia

    Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  3. wire chamber

    CERN Multimedia

    Was used in ISR (Intersecting Storage Ring) split field magnet experiment. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  4. Composite of TiN nanoparticles and few-walled carbon nanotubes and its application to the electrocatalytic oxygen reduction reaction

    KAUST Repository

    Isogai, Shunsuke

    2011-11-30

    Nanoparticles meet nanotubes! Direct synthesis of TiN nanoparticles in a three-dimensional network of few-walled carbon nanotubes (FWCNTs) was achieved by using mesoporous graphitic carbon nitride (C 3N 4) as both a hard template and a nitrogen source. The TiN/FWCNT composite showed high performance for the oxygen reduction reaction in acidic media. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol...... in the chamber with time. Four different spacers were connected via filters to a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London...

  6. Functionalization of multi-walled carbon nanotubes with iron phthalocyanine via a liquid chemical reaction for oxygen reduction in alkaline media

    Science.gov (United States)

    Yan, Xiaomei; Xu, Xiao; Liu, Qin; Guo, Jia; Kang, Longtian; Yao, Jiannian

    2018-06-01

    Iron single-atom catalyst in form of iron-nitrogen-carbon structure possesses the excellent catalytic activity in various chemical reactions. However, exploring a sustainable and stable single-atom metal catalyst still faces a great challenge due to low yield and complicated synthesis. Here, we report a functional multi-wall carbon nanotubes modified with iron phthalocyanine molecules via a liquid chemical reaction and realize the performance of similar single-atom catalysis for oxygen reduction reaction. A serial of characterizations strongly imply the structure change of iron phthalocyanine molecule and its close recombination with multi-wall carbon nanotubes, which are in favor of ORR catalysis. Compared to commercial platinum-carbon catalyst, composites exhibit superior activity for oxygen reduction reaction with higher half-wave potential (0.86 V), lower Tafel slope (38 mV dec-1), higher limiting current density and excellent electrochemical stability. The corresponding Zinc-air battery also presents higher maximum power density and discharge stability. Therefore, these findings provide a facile route to synthesize a highly efficient non-precious metal carbon-based catalyst.

  7. Physical modelling of near-wall phenomena in entrained-flow coal gasifiers

    OpenAIRE

    Troiano, Maurizio

    2015-01-01

    Combustion and gasification under slagging conditions are key aspects of the design of modern entrained-flow reactors for thermal conversion of solid fuels, aimed at increasing the overall energy efficiency. In these systems, solid particles migrate toward the reactor walls, due to swirled/tangential flow induced in the reaction chamber and to turbophoresis, generating, thanks to the very high operating temperatures, a slag layer that flows along the reactor internal walls and is drained to t...

  8. Peltier-based cloud chamber

    Science.gov (United States)

    Nar, Sevda Yeliz; Cakir, Altan

    2018-02-01

    Particles produced by nuclear decay, cosmic radiation and reactions can be identified through various methods. One of these methods that has been effective in the last century is the cloud chamber. The chamber makes visible cosmic particles that we are exposed to radiation per second. Diffusion cloud chamber is a kind of cloud chamber that is cooled by dry ice. This traditional model has some application difficulties. In this work, Peltier-based cloud chamber cooled by thermoelectric modules is studied. The new model provided uniformly cooled base of the chamber, moreover, it has longer lifetime than the traditional chamber in terms of observation time. This gain has reduced the costs which spent each time for cosmic particle observation. The chamber is an easy-to-use system according to traditional diffusion cloud chamber. The new model is portable, easier to make, and can be used in the nuclear physics experiments. In addition, it would be very useful to observe Muons which are the direct evidence for Lorentz contraction and time expansion predicted by Einsteins special relativity principle.

  9. Correction of effects due to reactions on complex nuclei in a sample of hydrogen-like antiproton annihilations from a heavy liquid bubble chamber experiment

    International Nuclear Information System (INIS)

    Fett, E.; Haatuft, A.; Olsen, J.M.

    1977-01-01

    A method is presented, which has been used to determine the pion multiplicity distributions for antiproton annihilations on free protons from a sample of events obtained in a heavy liquid bubble chamber experiment. The method uses data obtained in the experiment in question together with the usual invariance principles satisfied by strong interactions. Furthermore no particular nuclear model is assumed

  10. Results from the MAC Vertex chamber

    International Nuclear Information System (INIS)

    Nelson, H.N.

    1987-05-01

    The design, construction, and performance characteristics of a high precision gaseous drift chamber made of thin walled proportional tubes are described. The device achieved an average spatial resolution of 45 μm in use for physics analysis with the MAC detector. The B-lifetime result obtained with this chamber is discussed

  11. A novel high performance stopped-flow apparatus equipped with a special constructed mixing chamber containing a plunger under inert condition with a very short dead-time to investigate very rapid reactions

    Directory of Open Access Journals (Sweden)

    Sayyed Mostafa Habibi Khorassani

    2015-11-01

    Full Text Available The present work set out to establish a novel stopped-flow instrument equipped with a special constructed mixing chamber containing a plunger to enable a kinetic study of the very rapid reactions under a dry inert atmosphere glove bag, in particular, for the reactions are sensitive to moisture or air. A stopped-flow spectrophotometer is essentially a conventional spectrophotometer with the addition of a system for rapid mixing of solutions. The purpose of this work is to describe the fabrication and evaluation of specially constructed and in-expensive stopped-flow system. The evaluation includes determination of the dead-time, relative mixing efficiency, and the measurement of known rate constants. Herein, a dead-time of about 3.4 ms was determined in the final modified construction of the stopped-flow apparatus in order to investigate the rapid initial during which some form of reaction intermediate is presented to be formed.

  12. Does Spending Money on Education Help? A Reaction to the Heritage Foundation and the "Wall Street Journal."

    Science.gov (United States)

    Wainer, Howard

    In June 1993 the "Wall Street Journal" carried a table of data prepared by the Heritage Foundation that listed the states in order of the average amount they expend on each public school student. The table also contained each state's rank on the average score on the Scholastic Aptitude Test (SAT) and the rank of each state in the average…

  13. Pelletron general purpose scattering chamber

    International Nuclear Information System (INIS)

    Chatterjee, A.; Kailas, S.; Kerekette, S.S.; Navin, A.; Kumar, Suresh

    1993-01-01

    A medium sized stainless steel scattering chamber has been constructed for nuclear scattering and reaction experiments at the 14UD pelletron accelerator facility. It has been so designed that several types of detectors, varying from small sized silicon surface barrier detectors to medium sized gas detectors and NaI detectors can be conveniently positioned inside the chamber for detection of charged particles. The chamber has been planned to perform the following types of experiments : angular distributions of elastically scattered particles, fission fragments and other charged particles, angular correlations for charged particles e.g. protons, alphas and fission fragments. (author). 2 figs

  14. Reaction

    African Journals Online (AJOL)

    abp

    19 oct. 2017 ... Reaction to Mohamed Said Nakhli et al. concerning the article: "When the axillary block remains the only alternative in a 5 year old child". .... Bertini L1, Savoia G, De Nicola A, Ivani G, Gravino E, Albani A et al ... 2010;7(2):101-.

  15. Chamber transport

    International Nuclear Information System (INIS)

    Olson, Craig L.

    2001-01-01

    Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system

  16. Bicone vacuum chamber for ISR intersection

    CERN Multimedia

    1975-01-01

    This is one of the bicone chambers made of titanium for experiment R 702. The central corrugated part had a very thin titanium wall (0.28 mm). The first of these chambers collapsed in its central part when baked at 300 C (August 1975). After an intensive effort to develop better quality and reproducible welds for this special material, the ISR workshop was able to build two new chambers of this type. One of them was installed at I 7 for R 702 in 1976 and worked perfectly. It was at that time the most "transparent" intersection vacuum chamber. See also 7609219, 7609221.

  17. Determination of the correction factor for attenuation, dispersion and production of electrons (K{sub wall}) in the wall of graphite of a ionization chamber Pattern National Type CC01 in fields of gamma radiation of {sup 60}Co; Determinacion del factor de correccion por atenuacion, dispersion y produccion de electrones (K{sub wall}) en la pared de grafito de una Camara de Ionizacion Patron Nacional Tipo CC01 en campos de radiacion gamma de {sup 60} Co

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J.T.; Morales P, J.; Cruz E, P. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2001-12-15

    It was determined the Kwall correction factor for the wall of graphite of the chamber of the pattern national type CC01 series 133 for a radiation field Gamma of {sup 60}Co. With this end to measured the currents of ionization l(x) as function of the thickness of the wall of the chamber: X=4,8,12,16 and 20 mm.The mensurations for each thickness consisting of three groups, of sizes n = 30 or 60 data for each group; obtaining 8 complete groups of mensurations independent in eight different dates.The determinate the factor carried out using three regression models: lineal, logarithmic and quadratic, models that were tried to validate with the tests of : i) Shapiro-Wilk and {chi}{sup 2} for the normality of the entrance data ii) Tests of Bartlett for variances homogeneity among groups for each thickness iii) The tests of Duncan for the stockings among groups of each thickness, and iv) The tests of adjustment lack (LOF) for the models used. Nevertheless, alone the models of the group of corresponding mensurations at 01-03-2000 17-08-2001 they can be validated by LOF, but not for tests of normality and homogeneity of variances. Among other assignable causes of variation we have: i) The values captured by the system of mensuration of the variables of it influences: pressure, temperature and relative humidity don{sup t} belong together with the existent ones to the moment to capture the l(x). ii) The mensuration room presents flows of air, for what was suited o diminish their volume and to eliminate the flows of air. iii) A protocol settled down of taking of measures that it consisted in: - Pre-irradiation 5 minutes the chamber after the change of polarity and hood change, with a period of stabilization of 5 minutes after the pre-irradiation. - Pre-irradiation for 5 minutes before the taking of the readings, with the object of eliminating variation sources assigned to currents of escapes or due variations to transitory. iv) To realize corrections for relative humidity of

  18. Scaling of the flow field in a combustion chamber with a gas–gas injector

    International Nuclear Information System (INIS)

    Xiao-Wei, Wang; Guo-Biao, Cai; Ping, Jin

    2010-01-01

    The scaling of the flow field in a gas–gas combustion chamber is investigated theoretically, numerically and experimentally. To obtain the scaling criterion of the gas–gas combustion flowfield, formulation analysis of the three-dimensional (3D) Navier–Stokes equations for a gaseous multi-component mixing reaction flow is conducted and dimensional analysis on the gas–gas combustion phenomena is also carried out. The criterion implies that the size and the pressure of the gas–gas combustion chamber can be changed. Based on the criterion, multi-element injector chambers with different geometric sizes and at different chamber pressures ranging from 3 MPa to 20 MPa are numerically simulated. A multi-element injector chamber is designed and hot-fire tested at five chamber pressures from 1.64 MPa to 3.68 MPa. Wall temperature measurements are used to understand the similarity of combustion flowfields in the tests. The results have verified the similarities between combustion flowfields under different chamber pressures and geometries, with the criterion applied. (geophysics, astronomy and astrophysics)

  19. Proceedings of workshop on streamer chamber

    International Nuclear Information System (INIS)

    Itoh, Hidihiko; Takahashi, Kaoru; Hirose, Tachishige; Masaike, Akira

    1978-08-01

    For high accuracy observation of multiple-body reactions, a vertex detector of high efficiency is essential. A bubble chamber, though excellent for tracks detection, is problematic in statistics accuracy. The vertex detector with a wire chamber, while better in this respect, difficult in multiple-particle detection etc. The workshop has had several meetings on a streamer chamber as a detector combining features of both bubble chamber and counter, with emphasis on tracks observation in avalanche mode and recordings not using films. Contents are on streamer chamber gas, analytical photography, data processing, simulation program, etc. (Mori, K.)

  20. Cultivable anaerobic and aerobic bacterial communities in the fermentation chambers of Holotrichia parallela (coleoptera: scarabaeidae) larvae.

    Science.gov (United States)

    Zhang, Zhen-Yu; Yuan, Yimin; Ali, Muhammad Waqar; Peng, Tao; Peng, Wei; Raza, Muhammad Fahim; Zhao, Yongshun; Zhang, Hongyu

    2018-01-01

    As important pests, scarab beetle larvae survive on plant biomass and the microbiota of the fermentation chamber play an important role in the digestion of lignocellulose-rich diets. However, the cultivable microbes, especially the anaerobic cultivable microbes, are still largely unknown. Here, both cultivable anaerobic and aerobic bacterial communities associated with the fermentation chamber of Holotrichia parallela larvae were investigated. In total bacteria cells directly enumerated by the 4', 6-diamidino-2-phenylindole (DAPI) staining method, the viable plate counts of cultivable bacteria in the fermentation chamber accounted for 0.92% of proportion. These cultivable bacteria were prone to attach to the fermentation chamber wall (88.41%) compared to the chamber contents. Anaerobic bacteria were dominant in the cultivable bacteria attaching to the fermentation chamber wall (70.20%), while the quantities of anaerobes and aerobes were similar in the chamber contents. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), fingerprinting and sequence analysis of isolated colonies revealed that the cultivable bacteria are affiliated with class γ-Proteobacteria, Bacteroidia, Actinobacteria, Clostridia and β-Proteobacteria. γ-Proteobacteria was the major type of anaerobic cultivable bacteria and even the only one type of aerobic cultivable bacteria. Taken together, our results suggest, for the first time, that anaerobic microbiota are dominant in cultivable bacteria in the special anoxia niche of the fermentation chamber from H. parallela larvae. These bacterial isolates could be a treasure trove for screening lignocellulytic microbes which are essential for the plant biomass digestion of this scarab species.

  1. Cultivable anaerobic and aerobic bacterial communities in the fermentation chambers of Holotrichia parallela (coleoptera: scarabaeidae) larvae

    Science.gov (United States)

    Ali, Muhammad Waqar; Peng, Tao; Peng, Wei; Raza, Muhammad Fahim; Zhao, Yongshun; Zhang, Hongyu

    2018-01-01

    As important pests, scarab beetle larvae survive on plant biomass and the microbiota of the fermentation chamber play an important role in the digestion of lignocellulose-rich diets. However, the cultivable microbes, especially the anaerobic cultivable microbes, are still largely unknown. Here, both cultivable anaerobic and aerobic bacterial communities associated with the fermentation chamber of Holotrichia parallela larvae were investigated. In total bacteria cells directly enumerated by the 4’, 6-diamidino-2-phenylindole (DAPI) staining method, the viable plate counts of cultivable bacteria in the fermentation chamber accounted for 0.92% of proportion. These cultivable bacteria were prone to attach to the fermentation chamber wall (88.41%) compared to the chamber contents. Anaerobic bacteria were dominant in the cultivable bacteria attaching to the fermentation chamber wall (70.20%), while the quantities of anaerobes and aerobes were similar in the chamber contents. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), fingerprinting and sequence analysis of isolated colonies revealed that the cultivable bacteria are affiliated with class γ-Proteobacteria, Bacteroidia, Actinobacteria, Clostridia and β-Proteobacteria. γ-Proteobacteria was the major type of anaerobic cultivable bacteria and even the only one type of aerobic cultivable bacteria. Taken together, our results suggest, for the first time, that anaerobic microbiota are dominant in cultivable bacteria in the special anoxia niche of the fermentation chamber from H. parallela larvae. These bacterial isolates could be a treasure trove for screening lignocellulytic microbes which are essential for the plant biomass digestion of this scarab species. PMID:29304141

  2. Plasma chemistry in wire chambers

    International Nuclear Information System (INIS)

    Wise, J.

    1990-05-01

    The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an 55 Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested except those containing methane, use of hygroscopic filters to remove trace water and oxygen contaminants from the gas resulted in an increase in the average molecular weight of the products, consistent with results from low-pressure rf-discharge plasmas. It is suggested that because water and oxygen inhibit polymer growth in the gas phase that they may also reduce polymer deposition in proportional tubes and therefore retard wire aging processes. Mechanistic implications of the plasma reactions of hydrocarbons with oxygen are suggested. Unresolved issues in this work and proposals for further study are discussed

  3. Study on the reactions dp → dpπ+π- and dp → dnπ+ at 33 GeV/c in the hydrogen bubble chamber

    International Nuclear Information System (INIS)

    Aladashvili, B.S.; Glagolev, V.V.; Gorbunov, A.N.; Khairetdinov, K.U.; Lebedev, R.M.; Nioradze, M.S.; Saitov, I.S.; Streltsov, V.N.

    1975-01-01

    A narrow singularity is observed in the effective mass spectrum in the dp → dpπ + π - and dp → dnπ + reactions at the incident deutron momentum of 3.3 GeV/c. The position and width of the singularity are (2,151+0.005) GeV and (13+6) MeV, respectively. The signal in the distribution of dπ + -mass at (2.294+0.005)GeV with the width of (47+13) MeV in reaction dp → dnπ + is identified as a kinematic effect

  4. Construction and performance of large flash chambers

    International Nuclear Information System (INIS)

    Taylor, F.E.; Bogert, D.; Fisk, R.; Stutte, L.; Walker, J.K.; Wolfson, J.; Abolins, M.; Ernwein, J.; Owen, D.; Lyons, T.

    1979-01-01

    The construction and performance of 12' x 12' flash chambers used in a 340 ton neutrino detector under construction at Fermilab is described. The flash chambers supply digital information with a spatial resolution of 0.2'', and are used to finely sample the shower development of the reaction products of neutrino interactions. The flash chambers are easy and inexpensive to build and are electronically read out

  5. Doriot Climatic Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — The Doriot Climatic Chambers are two, 60-feet long, 11-feet high, 15-feet wide chambers that are owned and operated by NSRDEC. The Doriot Climatic Chambers are among...

  6. Defect-induced Catalysis toward the Oxygen Reduction Reaction in Single-walled Carbon Nanotube: Nitrogen doped and Non-nitrogen doped

    International Nuclear Information System (INIS)

    Lu, Di; Wu, Dan; Jin, Jian; Chen, Liwei

    2016-01-01

    Single-walled carbon nanotubes (SWNTs) are post-treated by argon (Ar) or ammonia (NH 3 ) plasma irradiation to introduce defects that are potentially related to catalysis towards the oxygen reduction reaction (ORR). Electrochemical characterization in alkali medium suggests that the plasma irradiated SWNTs demonstrate enhanced catalytic activity toward the ORR with a positively shifted threshold potential. Moreover the enhanced desired four-electron pathway catalytic activity, which exhibited as the positive shifted threshold potential, is independent of the nitrogen dopant. The nature of the defects is probed with Raman and X-ray photoelectron spectroscopy. The results indicate that the non-nitrogen doped defects of SWNTs contribute to the actual active site for the ORR.

  7. Effectively enhanced load transfer by interfacial reactions in multi-walled carbon nanotube reinforced Al matrix composites

    International Nuclear Information System (INIS)

    Zhou, Weiwei; Yamaguchi, Tatsuya; Kikuchi, Keiko; Nomura, Naoyuki; Kawasaki, Akira

    2017-01-01

    The thermal expansion response of multi-walled carbon nanotube (MWCNT) reinforced Al matrix composites was employed to discuss the improvement of the load transfer at the interface between the MWCNTs and the Al matrix. An aluminum carbide (Al_4C_3) nanostructure at the end of the MWCNTs, incorporated in the Al matrix, was produced by appropriate heat-treatment. The stress contrast around the Al_4C_3 observed in the high-resolution transmission electron microscopy (HRTEM) image revealed the evidence of a trace of friction, which would lead to the enhancement of the anchor effect from the Al matrix. This anchor effect of Al_4C_3 may hinder the local interfacial slippage and constrain the deformation of the Al matrix. As a result, the thermal expansion behavior became linear and reversible under cyclic thermal load. It is concluded that the formation of Al_4C_3 could effectively enhance the load transfer in MWCNT/Al composites. The yield strength of MWCNT/Al composites was substantially increased under the appropriate quantity of Al_4C_3 produced at the MWCNT-Al interface by precisely controlled heat-treatment.

  8. Periodontal tissue reaction to customized nano-hydroxyapatite block scaffold in one-wall intrabony defect: a histologic study in dogs.

    Science.gov (United States)

    Lee, Jung-Seok; Park, Weon-Yeong; Cha, Jae-Kook; Jung, Ui-Won; Kim, Chang-Sung; Lee, Yong-Keun; Choi, Seong-Ho

    2012-04-01

    This study evaluated histologically the tissue responses to and the effects of a customized nano-hydroxyapatite (n-HA) block bone graft on periodontal regeneration in a one-wall periodontal-defect model. A customized block bone for filling in the standardized periodontal defect was fabricated from prefabricated n-HA powders and a polymeric sponge. Bilateral 4×4×5 mm (buccolingual width×mesiodistal width×depth), one-wall, critical-size intrabony periodontal defects were surgically created at the mandibular second and fourth premolars of five Beagle dogs. In each dog, one defect was filled with block-type HA and the other served as a sham-surgery control. The animals were sacrificed following an 8-week healing interval for clinical and histological evaluations. Although the sites that received an n-HA block showed minimal bone formation, the n-HA block was maintained within the defect with its original hexahedral shape. In addition, only a limited inflammatory reaction was observed at sites that received an n-HA block, which might have been due to the high stability of the customized block bone. In the limitation of this study, customized n-HA block could provide a space for periodontal tissue engineering, with minimal inflammation.

  9. [Characterization of photochemical smog chamber and initial experiments].

    Science.gov (United States)

    Jia, Long; Xu, Yong-Fu; Shi, Yu-Zhen

    2011-02-01

    A self-made new indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosols has been introduced and characterized. The characterization experiments include the measurements of wall effects for reactive species and the determination of chamber dependent * OH radical sources by CO-NO(x) irradiation experiments. Preliminary ethene-NO(x) and benzene-NO(x) experiments were conducted as well. The results of characterization experiments show that the wall effects for O3 and NO2 in a new reactor are not obvious. Relative humidity has a great effect on the wall losses in the old reactor, especially for O3. In the old reactor, the rate constant for O3 wall losses is obtained to be 1.0 x 10(-5) s(-1) (RH = 5%) and 4.0 x10(-5) s(-1) (RH = 91%), whereas for NO2, it is 1.0 x 10(-6) s(-1) (RH = 5%) and 0.6 x 10(-6) s(-1) (RH = 75%). The value for k(NO2 --> HONO) determined by CO-NO(x) irradiation experiments is (4.2-5.2) x 10(-5) s(-1) and (2.3-2.5) x 10(-5) s(-1) at RH = 5% and RH 75% -77%, respectively. The average *OH concentration is estimated to be (2.1 +/- 0.4) x 10(6) molecules/cm3 by using a reaction rate coefficient of CO and * OH. The sensitivity of chamber dependent auxiliary reactions to the O3 formation is discussed. Results show that NO2 --> HONO has the greatest impact on the O3 formation during the initial stage, N2O5 + H2O --> 2HNO3 has a minus effect to maximum O3 concentration, and that the wall losses of both O3 and NO2 have little impact on the O3 formation. The results from the ethene-NO(x) and benzene-NO(x) experiments are in good agreement with those from the MCM simulation, which reflects that the facility for the study of the formation of secondary pollution of ozone and secondary organic aerosols is reliable. This demonstrates that our facility can be further used in the deep-going study of chemical processes in the atmosphere.

  10. Directed Energy Anechoic Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — The Directed Energy Anechoic Chamber comprises a power anechoic chamber and one transverse electromagnetic cell for characterizing radiofrequency (RF) responses of...

  11. Multiple chamber ionization detector

    International Nuclear Information System (INIS)

    Solomon, E.E.

    1980-01-01

    A multi-chambered ionisation detector enables the amount of radiation entering each chamber from a single radioactive, eg β, source to be varied by altering the proportion of the source protruding into each chamber. Electrodes define chambers and an extended radioactive source is movable to alter the source length in each chamber. Alternatively, the source is fixed relative to outer electrodes but the central electrode may be adjusted by an attached support altering the chamber dimensions and hence the length of source in each. Also disclosed are a centrally mounted source tiltable towards one or other chamber and a central electrode tiltable to alter chamber dimensions. (U.K.)

  12. 46 CFR 59.15-5 - Stayed furnaces and combustion chambers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Stayed furnaces and combustion chambers. 59.15-5 Section... and combustion chambers. (a) Where the plate forming the walls of stayed furnaces or combustion... wall of a stayed furnace or combustion chamber, the defective portion of the plate shall be cut away...

  13. HYLIFE-II reactor chamber design refinements

    International Nuclear Information System (INIS)

    House, P.A.

    1994-06-01

    Mechanical design features of the reactor chamber for the HYLIFE-II inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams (Li 2 BeF 4 ) are used for shielding and blast protection of the chamber walls. The system is designed for a 6 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (>12 m/s) salt streams and also recover up to half of the dynamic head. Cost estimates for a 1 GWe and 2 GWe reactor chamber are presented

  14. Near wall combustion modeling in spark ignition engines. Part A: Flame–wall interaction

    International Nuclear Information System (INIS)

    Demesoukas, Sokratis; Caillol, Christian; Higelin, Pascal; Boiarciuc, Andrei; Floch, Alain

    2015-01-01

    Highlights: • A model for flame–wall interaction in addition to flame wrinkling by turbulence is proposed. • Two sparkplug positions and two lengths are used in a test engine for model validation. • Flame–wall interaction decreases the maximum values of cylinder pressure and heat release rates. • The impact of combustion chamber geometry is taken into account by the flame–wall interaction model. - Abstract: Research and design in the field of spark ignition engines seek to achieve high performance while conserving fuel economy and low pollutant emissions. For the evaluation of various engine configurations, numerical simulations are favored, since they are quick and less expensive than experiments. Various zero-dimensional combustion models are currently used. Both flame front reactions and post-flame processes contribute to the heat release rate. The first part of this study focuses on the role of the flame front on the heat release rate, by modeling the interaction of the flame front with the chamber wall. Post-flame reactions are dealt with in Part B of the study. The basic configurations of flame quenching in laminar flames are also applicable in turbulent flames, which is the case in spark ignition engines. A simplified geometric model of the combustion chamber was used to calculate the mean flame surface, the flame volume and the distribution of flame surface as a function of the distance from the wall. The flame–wall interaction took into account the geometry of the combustion chamber and of the flame, aerodynamic turbulence and the in-cylinder pressure and temperature conditions, through a phenomenological attenuation function of the wrinkling factor. A modified global wrinkling factor as a function of the mean surface distance distribution from the wall was calculated. The impact of flame–wall interaction was simulated for four configurations of the sparkplug position and length: centered and lateral position, and standard and projected

  15. Determination of the thermal and epithermal neutron sensitivities of an LBO chamber

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Satoru; Kotani, Kei; Kajimoto, Tsuyoshi; Tanaka, Kenichi [Hiroshima University, Quantum Energy Applications, Graduate School of Engineering, Higashi-Hiroshima (Japan); Sato, Hitoshi; Nakajima, Erika [Ibaraki Prefectural University of Health Science, Radiological Sciences, Ibaraki (Japan); Shimazaki, Takuto [Hiroshima University, Quantum Energy Applications, Graduate School of Engineering, Higashi-Hiroshima (Japan); Delta Kogyo Co., Ltd., Hiroshima (Japan); Suda, Mitsuru; Hamano, Tsuyoshi [National Institute of Radiological Sciences, Chiba-Shi, Chiba (Japan); Hoshi, Masaharu [Hiroshima University, Institute for Peace Science, Hiroshima (Japan)

    2017-08-15

    An LBO (Li{sub 2}B{sub 4}O{sub 7}) walled ionization chamber was designed to monitor the epithermal neutron fluence in boron neutron capture therapy clinical irradiation. The thermal and epithermal neutron sensitivities of the device were evaluated using accelerator neutrons from the {sup 9}Be(d, n) reaction at a deuteron energy of 4 MeV (4 MeV d-Be neutrons). The response of the chamber in terms of the electric charge induced in the LBO chamber was compared with the thermal and epithermal neutron fluences measured using the gold-foil activation method. The thermal and epithermal neutron sensitivities obtained were expressed in units of pC cm{sup 2}, i.e., from the chamber response divided by neutron fluence (cm{sup -2}). The measured LBO chamber sensitivities were 2.23 x 10{sup -7} ± 0.34 x 10{sup -7} (pC cm{sup 2}) for thermal neutrons and 2.00 x 10{sup -5} ± 0.12 x 10{sup -5} (pC cm{sup 2}) for epithermal neutrons. This shows that the LBO chamber is sufficiently sensitive to epithermal neutrons to be useful for epithermal neutron monitoring in BNCT irradiation. (orig.)

  16. Radon progeny distribution in cylindrical diffusion chambers

    International Nuclear Information System (INIS)

    Pressyanov, Dobromir S.

    2008-01-01

    An algorithm to model the diffusion of radioactive decay chain atoms is presented. Exact mathematical solutions in cylindrical geometry are given. They are used to obtain expressions for the concentrations of 222 Rn progeny atoms in the volume and deposited on the wall surface in cylindrical diffusion chambers. The dependence of volume fractions of 222 Rn progeny and chamber sensitivity on the coefficient of diffusion of 222 Rn progeny atoms in air is modeled.

  17. Making MUSIC: A multiple sampling ionization chamber

    International Nuclear Information System (INIS)

    Shumard, B.; Henderson, D.J.; Rehm, K.E.; Tang, X.D.

    2007-01-01

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the (α, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for (α, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only (α, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. x 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the (α, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the (α, p) reaction to reach the anode segment below the reaction

  18. Making MUSIC: A multiple sampling ionization chamber

    Science.gov (United States)

    Shumard, B.; Henderson, D. J.; Rehm, K. E.; Tang, X. D.

    2007-08-01

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the (α, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for (α, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only (α, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. × 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the (α, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the (α, p) reaction to reach the anode segment below the reaction.

  19. Making MUSIC: A multiple sampling ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Shumard, B. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States)]. E-mail: shumard@phy.anl.gov; Henderson, D.J. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States); Rehm, K.E. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States); Tang, X.D. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States)

    2007-08-15

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the ({alpha}, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for ({alpha}, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only ({alpha}, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. x 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the ({alpha}, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the ({alpha}, p) reaction to reach the anode segment below the reaction.

  20. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  1. Glove box chamber

    International Nuclear Information System (INIS)

    Cox, M.E.; Cox, M.E.

    1975-01-01

    An environmental chamber is described which enables an operator's hands to have direct access within the chamber without compromising a special atmosphere within such chamber. A pair of sleeves of a flexible material are sealed to the chamber around associated access apertures and project outwardly from such chamber. Each aperture is closed by a door which is openable from within the sleeve associated therewith so that upon an operator inserting his hand and arm through the sleeve, the operator can open the door to have access to the interior of the chamber. A container which is selectively separable from the remainder of the chamber is also provided to allow objects to be transferred from the chamber without such objects having to pass through the ambient atmosphere. An antechamber permitting objects to be passed directly into the chamber from the ambient atmosphere is included. (auth)

  2. Hot wire production of single-wall and multi-wall carbon nanotubes

    Science.gov (United States)

    Dillon, Anne C.; Mahan, Archie H.; Alleman, Jeffrey L.

    2010-10-26

    Apparatus (210) for producing a multi-wall carbon nanotube (213) may comprise a process chamber (216), a furnace (217) operatively associated with the process chamber (216), and at least one filament (218) positioned within the process chamber (216). At least one power supply (220) operatively associated with the at least one filament (218) heats the at least one filament (218) to a process temperature. A gaseous carbon precursor material (214) operatively associated with the process chamber (216) provides carbon for forming the multi-wall carbon nanotube (213). A metal catalyst material (224) operatively associated with the process (216) catalyzes the formation of the multi-wall carbon nanotube (213).

  3. Technique for measuring the losses of alpha particles to the wall in TFTR

    International Nuclear Information System (INIS)

    England, A.C.

    1984-03-01

    It is proposed to measure the losses of alpha particles to the wall in the Tokamak Fusion Test Reactor (TFTR) or any large deuterium-tritium (D-T) burning tokamak by a nuclear technique. For this purpose, a chamber containing a suitable fluid would be mounted near the wall of the tokamak. Alpha particles would enter the chamber through a thin window and cause nuclear reactions in the fluid. The material would then be transported through a tube to a remote, low-background location for measurement of the activity. The most favorable reaction suggested here is 10 B(α,n) 13 N, although 14 N(α,γ) 18 F and others may be possible. The system, the sensitivity, the probe design, and the sources of error are described

  4. Effects of Ramped Wall Temperature on Unsteady Two-Dimensional Flow Past a Vertical Plate with Thermal Radiation and Chemical Reaction

    Directory of Open Access Journals (Sweden)

    V. Rajesh

    2014-08-01

    Full Text Available The interaction of free convection with thermal radiation of a viscous incompressible unsteady flow past a vertical plate with ramped wall temperature and mass diffusion is presented here, taking into account the homogeneous chemical reaction of first order. The fluid is gray, absorbing-emitting but non-scattering medium and the Rosseland approximation is used to describe the radiative flux in the energy equation. The dimensionless governing equations are solved using an implicit finite-difference method of the Crank-Nicolson type, which is stable and convergent. The velocity profiles are compared with the available theoretical solution and are found to be in good agreement. Numerical results for the velocity, the temperature, the concentration, the local and average skin friction, the Nusselt number and Sherwood number are shown graphically. This work has wide application in chemical and power engineering and also in the study of vertical air flow into the atmosphere. The present results can be applied to an important class of flows in which the driving force for the flow is provided by combination of the thermal and chemical species diffusion effects.

  5. Ultrasensitive electrochemical detection of microRNA-21 combining layered nanostructure of oxidized single-walled carbon nanotubes and nanodiamonds by hybridization chain reaction.

    Science.gov (United States)

    Liu, Lingzhi; Song, Chao; Zhang, Zhang; Yang, Juan; Zhou, Lili; Zhang, Xing; Xie, Guoming

    2015-08-15

    Measurement of microRNA (miRNA) levels in body fluids is a crucial tool for the early diagnosis and prognosis of cancers. In this study, we developed an electrochemical assay to detect miRNA-21 by fabricating the electrode with layer-by-layer assembly of oxidized single-walled carbon nanotubes and nanodiamonds. Tetrahedron-structured probes with free-standing probe on the top served as receptors to hybridize with target miRNA directly. The probes were immobilized on the deposited gold nanoparticles through a well-established strong Au-S bond. The electrochemical signal was mainly derived from an ultrasensitive pattern by combining hybridization chain reaction with DNA-functionalized AuNPs, which provided DNAzyme to catalyze H2O2 reduction. Differential pulse voltammetry was applied to record the electrochemical signals, which was increased linearly with the target miRNA-21, and the linear detection range was 10 fM to 1.0 nM. The limit of detection reached 1.95 fM (S/N=3), and the proposed biosensor exhibited good reproducibility and stability, as well as high sensitivity. Hence, this biosensor has a promising potential in clinical application. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Open-air ionisation chambers with walls of soft-tissue equivalent material for measuring photon doses; Chambres d'ionisation d'ambiance a parois en materiau equivalent aux tissus mous pour la mesure des doses absorbees dues aux photons

    Energy Technology Data Exchange (ETDEWEB)

    Vialettes, H.; Anceau, J.C.; Grand, M.; Petit, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    The ionisation chambers presented in this report constitute a contribution to research into methods of carrying out correct determinations in the field of health physics. The use of a mixture of teflon containing 42.5 per cent by weight of carbon for the chamber walls makes it possible to measure directly the dose absorbed in air through 300 mg/cm{sup 2} of soft tissue and, consequently, the dose absorbed in the soft tissues with a maximum error of 10 per cent for photon energies of between 10 keV and 10 MeV. Furthermore since this material does not contain hydrogen, the chamber has a sensitivity to neutrons which is much less than other chambers in current use. Finally the shape of these chambers has been studied with a view to obtaining a satisfactory measurement from the isotropy point of view; for example for gamma radiation of 27 keV, the 3 litre chamber is isotropic to within 10 per cent over 270 degrees, and the 12 litre chamber is isotropic to within 10 per cent over 300 degrees; for 1.25 MeV gamma radiation this range is extended over 330 degrees for the 3 litre chamber, and 360 degrees for the 12 litre chamber. This report presents the measurements carried out with these chambers as well as the results obtained. These results are then compared to those obtained with other chambers currently used in the field of health physics. (authors) [French] Les chambres d'ionisation presentees dans ce rapport apportent une contribution a la recherche de moyens dosimetriques adaptes aux mesures a effectuer pour assurer une dosimetrie correcte dans le domaine de la radioprotection. L'utilisation d'un melange de teflon charge a 42.5 pour cent en masse de carbone comme materiau constituant les parois de la chambre permet de realiser un dosimetre mesurant directement la dose absorbee dans l'air sous 3OO mg/cm{sup 2} de tissu mou et, par consequent, la dose absorbee dans les tissus mous avec une erreur maximale de 10 pour cent, pour des photons d

  7. Lifetime tests for MAC vertex chamber

    International Nuclear Information System (INIS)

    Nelson, H.N.

    1986-07-01

    A vertex chamber for MAC was proposed to increase precision in the measurement of the B hadron and tau lepton lifetimes. Thin-walled aluminized mylar drift tubes were used for detector elements. A study of radiation hardness was conducted under the conditions of the proposed design using different gases and different operating conditions

  8. A drift chamber constructed of aluminized mylar tubes

    International Nuclear Information System (INIS)

    Baringer, P.; Jung, C.; Ogren, H.O.; Rust, D.R.

    1987-01-01

    A thin reliable drift chamber has been constructed to be used near the interaction point of the PEP storage ring in the HRS detector. It is composed of individual drift tubes with aluminized mylar walls. (orig.)

  9. A drift chamber constructed of aluminized mylar tubes

    Science.gov (United States)

    Baringer, P.; Jung, C.; Ogren, H. O.; Rust, D. R.

    1987-03-01

    A thin reliable drift chamber has been constructed to be used near the interaction point of the PEP storage ring in the HRS detector. It is composed of individual drift tubes with aluminized mylar walls.

  10. The atmosphere simulation chamber SAPHIR: a tool for the investigation of photochemistry.

    Science.gov (United States)

    Brauers, T.; Bohn, B.; Johnen, F.-J.; Rohrer, R.; Rodriguez Bares, S.; Tillmann, R.; Wahner, A.

    2003-04-01

    On the campus of the Forschungszentrum Jülich we constructed SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) which was accomplished in fall 2001. The chamber consists of a 280-m^3 double-wall Teflon bag of cylindrical shape that is held by a steel frame. Typically 75% of the outside actinic flux (290~nm~--~420~nm) is available inside the chamber. A louvre system allows switching between full sun light and dark within 40 s giving the opportunity to study relaxation processes of the photo chemical system. The SAPHIR chamber is equipped with a comprehensive set of sensitive instruments including the measurements of OH, HO_2, CO, hydrocarbons, aldehydes, nitrogen-oxides and solar radiation. Moreover, the modular concept of SAPHIR allows fast and flexible integration of new instruments and techniques. In this paper we will show the unique and new features of the SAPHIR chamber, namely the clean air supply and high purity water vapor supply providing a wide range of trace gas concentrations being accessible through the experiments. We will also present examples from the first year of SAPHIR experiment showing the scope of application from high quality instrument inter-comparison and kinetic studies to the simulation of complex mixtures of trace gases at ambient concentrations.

  11. Dual ionization chamber

    International Nuclear Information System (INIS)

    Mallory, J.; Turlej, Z.

    1981-01-01

    Dual ionization chambers are provided for use with an electronic smoke detector. The chambers are separated by electrically-conductive partition. A single radiation source extends through the partition into both chambers, ionizing the air in each. The mid-point current of the device may be balanced by adjusting the position of the source

  12. Design and performance of a straw tube drift chamber

    Science.gov (United States)

    Oh, S. H.; Wesson, D. K.; Cooke, J.; Goshaw, A. T.; Robertson, W. J.; Walker, W. D.

    1991-06-01

    The design and performance of the straw drift chambers used in E735 is reported. The chambers are constructed from 2.5 cm radius aluminized mylar straw tubes with wall thickness less than 0.2 mm. Also, presented are the results of tests with 2 mm radius straw tubes. The small tube has a direct detector application at the Superconducting Super Collider.

  13. Double chamber ion source

    International Nuclear Information System (INIS)

    Uman, M.F.; Winnard, J.R.; Winters, H.F.

    1978-01-01

    The ion source is comprised of two discharge chambers one of which is provided with a filament and an aperture leading into the other chamber which in turn has an extraction orifice. A low voltage arc discharge is operated in an inert gas atmosphere in the filament chamber while an arc of higher voltage is operated in the second ionization chamber which contains a vapor which will give the desired dopant ion species. The entire source is immersed in an axial magnetic field parallel to a line connecting the filament, the aperture between the two chambers and the extraction orifice. (author)

  14. Effects of ionization chamber construction on dose measurements in a heterogeneity

    International Nuclear Information System (INIS)

    Mauceri, T.; Kase, K.

    1987-01-01

    Traditionally, measurements have been made in heterogeneous phantoms to determine the factors which should be applied to dose calculations, when calculating a dose to a heterogeneous medium. Almost all measurements have relied on relatively thin-walled ion chambers, with no attempt to match ion chamber wall material to the measuring medium. The recent AAPM dosimetry protocol has established that a mismatch between ion chamber wall and phantom material can have an effect on dose measurement. To investigate the affect of this mismatch of ion chamber wall material to phantom material, two parallel-plate ion chambers were constructed. One ion chamber from solid water, for measurements in a solid water phantom and the other from plastic lung material, for measurements in a plastic lung material phantom. Correction factors measured by matching ion chamber to media were compared to correction factors measured by using a thin-walled cavity ion chamber with no regard for matching wall and media for cobalt-60, 6-, 10- and 20-MV photon beams. The results demonstrated that the matching of ion chamber to measuring media can be ignored, provided that a small, approximately tissue-equivalent, thin-walled ion chamber is used for measuring the correction factors

  15. Multi-chamber nucleic acid amplification and detection device

    Science.gov (United States)

    Dugan, Lawrence

    2017-10-25

    A nucleic acid amplification and detection device includes an amplification cartridge with a plurality of reaction chambers for containing an amplification reagent and a visual detection reagent, and a plurality of optically transparent view ports for viewing inside the reaction chambers. The cartridge also includes a sample receiving port which is adapted to receive a fluid sample and fluidically connected to distribute the fluid sample to the reaction chamber, and in one embodiment, a plunger is carried by the cartridge for occluding fluidic communication to the reaction chambers. The device also includes a heating apparatus having a heating element which is activated by controller to generate heat when a trigger event is detected. The heating apparatus includes a cartridge-mounting section which positioned a cartridge in thermal communication with the heating element so that visual changes to the contents of the reaction chambers are viewable through the view ports.

  16. Design, development, and demonstration of a fully LabVIEW controlled in situ electrochemical Fourier transform infrared setup combined with a wall-jet electrode to investigate the electrochemical interface of nanoparticulate electrocatalysts under reaction conditions.

    Science.gov (United States)

    Nesselberger, Markus; Ashton, Sean J; Wiberg, Gustav K H; Arenz, Matthias

    2013-07-01

    We present a detailed description of the construction of an in situ electrochemical ATR-FTIR setup combined with a wall-jet electrode to investigate the electrocatalytic properties of nanoparticulate catalysts in situ under controlled mass transport conditions. The presented setup allows the electrochemical interface to be probed in combination with the simultaneous determination of reaction rates. At the same time, the high level of automation allows it to be used as a standard tool in electrocatalysis research. The performance of the setup was demonstrated by probing the oxygen reduction reaction on a platinum black catalyst in sulfuric electrolyte.

  17. Streamer chamber: pion decay

    CERN Multimedia

    1992-01-01

    The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.

  18. Prototype multiwire proportional chamber

    CERN Multimedia

    1975-01-01

    Chambers of this type were initially developed within the Alpha project (finally not approved). They were designed such to minimize the radiation length with a view to a mass spectrometer of high resolution meant to replace the Omega detector. The chambers were clearly forerunners for the (drift) chambers later built for R606 with the novel technique of crimping the wires. See also photo 7510039X.

  19. Electromagnetic reverberation chambers

    CERN Document Server

    Besnier, Philippe

    2013-01-01

    Dedicated to a complete presentation on all aspects of reverberation chambers, this book provides the physical principles behind these test systems in a very progressive manner. The detailed panorama of parameters governing the operation of electromagnetic reverberation chambers details various applications such as radiated immunity, emissivity, and shielding efficiency experiments.In addition, the reader is provided with the elements of electromagnetic theory and statistics required to take full advantage of the basic operational rules of reverberation chambers, including calibration proc

  20. Monte Carlo modeling of ion chamber performance using MCNP.

    Science.gov (United States)

    Wallace, J D

    2012-12-01

    Ion Chambers have a generally flat energy response with some deviations at very low (2 MeV) energies. Some improvements in the low energy response can be achieved through use of high atomic number gases, such as argon and xenon, and higher chamber pressures. This work looks at the energy response of high pressure xenon-filled ion chambers using the MCNP Monte Carlo package to develop geometric models of a commercially available high pressure ion chamber (HPIC). The use of the F6 tally as an estimator of the energy deposited in a region of interest per unit mass, and the underlying assumptions associated with its use are described. The effect of gas composition, chamber gas pressure, chamber wall thickness, and chamber holder wall thicknesses on energy response are investigated and reported. The predicted energy response curve for the HPIC was found to be similar to that reported by other investigators. These investigations indicate that improvements to flatten the overall energy response of the HPIC down to 70 keV could be achieved through use of 3 mm-thick stainless steel walls for the ion chamber.

  1. DORIOT CLIMATIC CHAMBERS

    Data.gov (United States)

    Federal Laboratory Consortium — The Doriot Climatic Chambers reproduce environmental conditions occurring anywhere around the world. They provide an invaluable service by significantly reducing the...

  2. Gas microstrip chambers

    International Nuclear Information System (INIS)

    McIntyre, P.M.; Barasch, E.F.; Bowcock, T.J.V.; Demroff, H.P.; Elliott, S.M.; Howe, M.R.; Lee, B.; Mazumdar, T.K.; Pang, Y.; Smith, D.D.; Wahl, J.; Wu, Y.; Yue, W.K.; Gaedke, R.M.; Vanstraelen, G.

    1992-01-01

    The gas microstrip chamber has been developed from concept to experimental system during the past three years. A pattern of anode and grid lines are microfabricated onto a dielectric substrate and configured as a high-resolution MWPC. Four recent developments are described: Suitable plastic substrates and lithography techniques for large-area chambers; non-planar silicon-based chambers for 20 μm resolution; integrated on-board synchronous front-end electronics and data buffering; and a porous silicon active cathode for enhanced efficiency and time response. The microstrip chamber appears to be a promising technology for applications in microvertex, tracking spectrometer, muon spectrometer, and transition radiation detection. (orig.)

  3. Scale testing of a partially confined blast chamber

    CSIR Research Space (South Africa)

    Grundling, W

    2012-10-01

    Full Text Available in pressure readings. A scale model of the blast chamber, Emily, was constructed with the addition of a pendulum plate hanging concentrically covering 65% of the open area. PURPOSE OF SCALED BLAST CHAMBER The purpose of this particular test is to evaluate... PHASE Illustrated in Figure 3 and 4 are the results obtained during testing of the scaled blast chamber. In both cases the pressure dissipates over time, showing pulsating behaviour as the shockwaves reflect off the chamber walls. By looking...

  4. Measurement of radon concentration in air employing Lucas chamber

    International Nuclear Information System (INIS)

    Machaj, B.

    1997-01-01

    The results of investigations aimed to determine the main features of radon concentration gauge in air, employing 0.17 L Lucas chamber, and air sample forced by an air pump are presented. For two hour sampling and measuring cycle time the dynamic error in the worst case (first read out) equals 5 % relative to the step jump of radon concentration. This is due to the increase of activity of the decay products in the chamber. It was observed that the short lived radon decay products (Po-218, Pb-214, Bi-214) are depositing on the walls of the chamber and they are not removed by flushing the chamber with air. (author)

  5. Sidewall Covalent Functionalization of Single Wall Carbon Nanotubes through C-N Bond Forming Reactions of Fluoronanotubes with Urea, Guanidine and Thiourea (Preprint)

    National Research Council Canada - National Science Library

    Pulikkathara, Merlyn X; Khabashesku, Valery N

    2007-01-01

    ...) as starting materials in the reactions with either urea, thiourea, or guanidine. Through these reactions, the derivatives with terminal amide and heteroamide groups on the nanotube sidewalls have been prepared...

  6. An electrodeless drift chamber

    International Nuclear Information System (INIS)

    Allison, J.; Barlow, R.J.; Bowdery, C.K.; Duerdoth, I.; Rowe, P.G.

    1982-01-01

    We describe a chamber in which the drift field is controlled by the deposition of electrostatic charge on an insulating surface. The chamber operates with good efficiency and precision for observed drift distances of up to 45 cm, promises to be extremely robust and adaptable and offers a very cheap way of making particle detectors. (orig.)

  7. High resolution drift chambers

    International Nuclear Information System (INIS)

    Va'vra, J.

    1985-07-01

    High precision drift chambers capable of achieving less than or equal to 50 μm resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs

  8. Plastic flashtube chambers

    International Nuclear Information System (INIS)

    Frisken, W.R.

    1977-01-01

    A brief discussion is given of the use and operation of plastic flashtube chambers. Gas leaks, electric pulsing, the glow discharge, and readout methods are considered. Three distinct problems with high rate applications deal with resolving time, dead time, and polarization/neutralization of the chamber

  9. Climatic chamber ergometer

    CSIR Research Space (South Africa)

    Atkins, AR

    1968-01-01

    Full Text Available The design and calibration of an ergometer for exercising subjects during calorimetric studies in the climate chamber, are described. The ergometer is built into the climatic chamber and forms an integral part of the whole instrumentation system foe...

  10. BEBC bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    Looking up into the interior of BEBC bubble chamber from the expansion cylinder. At the top of the chamber two fish-eye lenses are installed and three other fish-eye ports are blanked off. In the centre is a heat exchanger.

  11. The Mobile Chamber

    Science.gov (United States)

    Scharfstein, Gregory; Cox, Russell

    2012-01-01

    A document discusses a simulation chamber that represents a shift from the thermal-vacuum chamber stereotype. This innovation, currently in development, combines the capabilities of space simulation chambers, the user-friendliness of modern-day electronics, and the modularity of plug-and-play computing. The Mobile Chamber is a customized test chamber that can be deployed with great ease, and is capable of bringing payloads at temperatures down to 20 K, in high vacuum, and with the desired metrology instruments integrated to the systems control. Flexure plans to lease Mobile Chambers, making them affordable for smaller budgets and available to a larger customer base. A key feature of this design will be an Apple iPad-like user interface that allows someone with minimal training to control the environment inside the chamber, and to simulate the required extreme environments. The feedback of thermal, pressure, and other measurements is delivered in a 3D CAD model of the chamber's payload and support hardware. This GUI will provide the user with a better understanding of the payload than any existing thermal-vacuum system.

  12. DELPHI time projection chamber

    CERN Multimedia

    1989-01-01

    The time projection chamber is inserted inside the central detector of the DELPHI experiment. Gas is ionised in the chamber as a charged particle passes through, producing an electric signal from which the path of the particle can be found. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  13. Effects of relative humidity on the characterization of a photochemical smog chamber.

    Science.gov (United States)

    Hu, Gaoshuo; Xu, Yongfu; Jia, Long

    2011-01-01

    Water vapor plays an important role in many atmospheric chemical reactions. A self-made indoor environmental smog chamber was used to investigate the effects of relative humidity (RH) on its characterization, which included the wall effects of reactive species such as 03 and NOx, and the determination of chamber-dependent OH radicals in terms of CO-NOx irradiation experiments. Results showed that the rate constant of O3 wall losses increased with increasing RH, and that their relationship was linearly significant. Although RH affected the rate constant of NOx wall losses, their relationship was not statistically significant. Background air generated a small amount of ozone at both high and low RH. When RH varied from 5% to 79%, the apparent rate constant kNO2-->HONO for the conversion of NO2 into gas phase HONO was estimated in the range of 0.70 x 10(-3)-2.5 x 10(-3) min(-1). A linear relationship between kNO2-->HONO and RH was obtained as kNO2-->HONO (10(-3) min(-1)) = -0.0255RH + 2.64, with R2 and P value being 0.978 and < 0.01. To our knowledge, this is the first report on their relationship. The generation mechanism for HONO and OH was also discussed in this work.

  14. Industrial development of neutron detectors, fission chambers, self powered detectors, ionization chambers

    International Nuclear Information System (INIS)

    Constans, H.; Coville, P.; Guerre, J.

    1975-01-01

    Reactor control requires the determination of neutron flux at all times. The needed characteristics lead to use of several types of detectors: boron lined counters, boron lined ionization chambers, fission ionization chambers and self powered detectors. The principle of the reaction involved the fabrication requirements, the different modes of utilization and the characteristics obtained are examined for each detector. The problem of electric connections in the active area has been solved by developing ''integrated cables'' [fr

  15. Lifetime tests for MAC vertex chamber

    International Nuclear Information System (INIS)

    Nelson, H.

    1986-01-01

    A vertex chamber for MAC was proposed in fall 1983 to increase precision in the measurement of the B hadron and tau lepton lifetimes. The chamber had to be placed within the existing central drift chamber, making access for repairs difficult and costly. Therefore for detector elements thin-walled aluminized mylar drift tubes (straws) were used because of their simplicity and robustness. The diameter of the drift tubes was 6.9 mm. The radial extent of the proposed chamber was from 3 cm to 10 cm, the inner wall of the central drift. It was clear that radiation levels, from synchrotron x-rays and overfocussed electrons, were potentially high. Since the drift distance is short in the straws, it was desirable to operate them at the highest possible gas gain, to achieve the best spatial resolution. There was a likelihood of drawing large currents in the chamber and thus causing radiation damage. Therefore a study of radiation hardness under the conditions of their proposed design was undertaken. In tests, argon-hydrocarbon mixtures consistently became unusable at ∼0.05 C/cm collected charge, due to anode buildup. Argon-CO 2 mixtures, while underquenched, were operational to 0.25 C/cm, at which point loss of cathode material became intolerable. Argon-xenon-CO 2 proved to be quenched as well as argon-hydrocarbons, but was limited by cathode damage. The MAC vertex chamber has operated at a distance of 4.6 cm from the e + e - interaction point at PEP for two years and has shown no aging effects

  16. OPAL Jet Chamber Prototype

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the dirfferent parts of the tracking system. This piece is a prototype of the jet chambers

  17. PS wire chamber

    CERN Multimedia

    1970-01-01

    A wire chamber used at CERN's Proton Synchrotron accelerator in the 1970s. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  18. Reconstruction of data in low-mass magnetostrictive chambers

    International Nuclear Information System (INIS)

    Daley, H.M.

    1983-01-01

    The reconstruction of spark positions in a set of low-mass spark chambers with remote magnetostrictive readout, used in a study of the reaction π - p → K 0 Λ, is described. The main detectors used were optical spark chambers but in order to provide information close to the vertices low-mass magnetostrictive chambers were fitted inside the cone of the superconducting polarised target magnet. (U.K.)

  19. Composite of TiN nanoparticles and few-walled carbon nanotubes and its application to the electrocatalytic oxygen reduction reaction

    KAUST Repository

    Isogai, Shunsuke; Ohnishi, Ryohji; Katayama, Masao; Kubota, Jun; Kim, Dongyoung; Noda, Suguru; Cha, Dong Kyu; Takanabe, Kazuhiro; Domen, Kazunari

    2011-01-01

    Nanoparticles meet nanotubes! Direct synthesis of TiN nanoparticles in a three-dimensional network of few-walled carbon nanotubes (FWCNTs) was achieved by using mesoporous graphitic carbon nitride (C 3N 4) as both a hard template and a nitrogen

  20. Acoustic-Levitation Chamber

    Science.gov (United States)

    Barmatz, M. B.; Granett, D.; Lee, M. C.

    1984-01-01

    Uncontaminated environments for highly-pure material processing provided within completely sealed levitation chamber that suspends particles by acoustic excitation. Technique ideally suited for material processing in low gravity environment of space.

  1. Optical spark chamber

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    An optical spark chamber developed for use in the Omega spectrometer. On the left the supporting frame is exceptionally thin to allow low momentum particles to escape and be detected outside the magnetic field.

  2. Vacuum chamber 'bicone'

    CERN Multimedia

    1977-01-01

    This chamber is now in the National Museum of History and Technology, Smithsonian Institution, Washington, DC, USA, where it was exposed in an exhibit on the History of High Energy Accelerators (1977).

  3. Miniature ionization chamber

    International Nuclear Information System (INIS)

    Alexeev, V.I.; Emelyanov, I.Y.; Ivanov, V.M.; Konstantinov, L.V.; Lysikov, B.V.; Postnikov, V.V.; Rybakov, J.V.

    1976-01-01

    A miniature ionization chamber having a gas-filled housing which accommodates a guard electrode made in the form of a hollow perforated cylinder is described. The cylinder is electrically associated with the intermediate coaxial conductor of a triaxial cable used as the lead-in of the ionization chamber. The gas-filled housing of the ionization chamber also accommodates a collecting electrode shaped as a rod electrically connected to the center conductor of the cable and to tubular members. The rod is disposed internally of the guard electrode and is electrically connected, by means of jumpers passing through the holes in the guard electrode, to the tubular members. The tubular members embrace the guard electrode and are spaced a certain distance apart along its entire length. Arranged intermediate of these tubular members are spacers secured to the guard electrode and fixing the collecting electrode throughout its length with respect to the housing of the ionization chamber

  4. Reference ionization chamber

    International Nuclear Information System (INIS)

    Golnik, N.; Zielczynski, M.

    1999-01-01

    The paper presents the design of ionization chamber devoted for the determination of the absolute value of the absorbed dose in tissue-equivalent material. The special attention was paid to ensure that the volume of the active gas cavity was constant and well known. A specific property of the chamber design is that the voltage insulators are 'invisible' from any point of the active volume. Such configuration ensures a very good time stability of the electrical field and defines the active volume. The active volume of the chamber was determined with accuracy of 0.3%. This resulted in accuracy of 0.8% in determination of the absorbed dose in the layer of material adherent to the gas cavity. The chamber was applied for calibration purposes at radiotherapy facility in Joint Institute for Nuclear Research in Dubna (Russia) and in the calibration laboratory of the Institute of Atomic Energy in Swierk. (author)

  5. Gridded ionization chamber

    International Nuclear Information System (INIS)

    Houston, J.M.

    1977-01-01

    An improved ionization chamber type x-ray detector comprises a heavy gas at high pressure disposed between an anode and a cathode. An open grid structure is disposed adjacent the anode and is maintained at a voltsge intermediate between the cathode and anode potentials. The electric field which is produced by positive ions drifting toward the cathode is thus shielded from the anode. Current measuring circuits connected to the anode are, therefore, responsive only to electron current flow within the chamber and the recovery time of the chamber is shortened. The grid structure also serves to shield the anode from electrical currents which might otherwise be induced by mechanical vibrations in the ionization chamber structure

  6. ALICE Time Projection Chamber

    CERN Multimedia

    Lippmann, C

    2013-01-01

    The Time Projection Chamber (TPC) is the main device in the ALICE 'central barrel' for the tracking and identification (PID) of charged particles. It has to cope with unprecedented densities of charges particles.

  7. To observe the intensity of the inflammatory reaction caused by neonatal urine and meconium on the intestinal wall of rats in order to understand etiology of intestinal damage in gastroschisis

    Directory of Open Access Journals (Sweden)

    Devdas S Samala

    2014-01-01

    Full Text Available Objectives: The aim of this experimental study was to observe the intensity of the inflammatory reaction caused by neonatal urine and meconium on the intestinal wall of rats to better understand etiology of intestinal damage in gastroschisis. Materials and Methods: A total of 24 adult Wistar rats were used as experimental models to simulate the effect of exposed bowel in cases of gastroschisis. The peritoneal cavity of the rats was injected with substances which constitute human amniotic fluid to study the effect on the bowel. Sterile urine and meconium were obtained from newborn humans. The rats were divided into four groups according to the material to be injected. In Group I (Control group 3 mL of distilled water was injected, in Group II (Urine group 3 mL of neonatal urine was injected, in Group III (Meconium group 5% meconium suspension was injected, while in Group IV, a combination of 5% meconium suspension and urine was injected. A total of 3mL solution was injected into the right inferior quadrant twice a day for 5 days. The animals were sacrificed on the 6 th day by a high dose of thiopentone sodium. A segment of small bowel specimen was excised, fixed in paraffin, and stained with hematoxylin-eosin for microscopic analysis for determination of the degree of inflammatory reaction in the intestinal wall. All pathology specimens were studied by the same pathologist. Results: The maximum bowel damage was seen in Group II (Urine group in the form of serositis, severe enteritis, parietal necrosis, and peeling. A lesser degree of damage was observed in Group III (Meconium group as mild enteritis (mild lymphoid hyperplasia. The least damage was seen in Group IV (Combination of meconium and urine and Group I (Control group. Conclusion: The intraabdominal injection of neonatal human urine produces significant inflammatory reactions in the intestinal wall of rats.

  8. Gridded Ionization Chamber

    International Nuclear Information System (INIS)

    Manero Amoros, F.

    1962-01-01

    In the present paper the working principles of a gridded ionization chamber are given, and all the different factors that determine its resolution power are analyzed in detail. One of these devices, built in the Physics Division of the JEN and designed specially for use in measurements of alpha spectroscopy, is described. finally the main applications, in which the chamber can be used, are shown. (Author) 17 refs

  9. Bubble chamber: antiproton annihilation

    CERN Multimedia

    1971-01-01

    These images show real particle tracks from the annihilation of an antiproton in the 80 cm Saclay liquid hydrogen bubble chamber. A negative kaon and a neutral kaon are produced in this process, as well as a positive pion. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  10. Mini-chamber, an advanced protection concept for NIF

    International Nuclear Information System (INIS)

    Peterson, P.F.; Scott, J.M.

    1996-01-01

    Inertial confinement fusion (ICF) target debris and ablated near-target materials pose the primary threat to the National Ignition Facility (NIF) final optics debris shields, as well as a major challenge in future inertial fusion energy (IFE) power plants. This work discusses a NIF 'mini-chamber,' designed to mitigate the debris threat. Although the NIF base-line design protects against debris using a frost-protected target positioner and refractory first-wall coatings, the mini-chamber provides important flexibility in three areas: debris-shield protection from beyond-design basis shots (i.e. heavy hohlraums, special diagnostics, shields); fielding of large experiments with significant surface ablation; and studying key ablation and gas-dynamics issues for liquid-wall IFE power plants. Key mini-chamber modeling results are presented, followed by discussion of equipment requirements for fielding a NIF mini-chamber. 7 refs., 3 figs

  11. HYLIFE-II reactor chamber mechanical design: Update

    International Nuclear Information System (INIS)

    House, P.A.

    1992-01-01

    Mechanical design features of the reactor chamber for the HYLIFE-II inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams (Li 2 BeF 4 ) are used for shielding and blast protection of the chamber walls. The system is designed for a 6 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (17 m/s) salt streams and also recover up to half of the dynamic head. Cost estimates for a 1 GW e and 2 GW e reactor chamber are presented

  12. Chamber technology concepts for inertial fusion energy: Three recent examples

    International Nuclear Information System (INIS)

    Meier, W.R.; Moir, R.W.; Abdou, M.A.

    1997-01-01

    The most serious challenges in the design of chambers for inertial fusion energy (IFE) are 1) protecting the first wall from fusion energy pulses on the order of several hundred megajoules released in the form of x rays, target debris, and high energy neutrons, and 2) operating the chamber at a pulse repetition rate of 5-10 Hz (i.e., re-establishing, the wall protection and chamber conditions needed for beam propagation to the target between pulses). In meeting these challenges, designers have capitalized on the ability to separate the fusion burn physics from the geometry and environment of the fusion chamber. Most recent conceptual designs use gases or flowing liquids inside the chamber. Thin liquid layers of molten salt or metal and low pressure, high-Z gases can protect the first wall from x rays and target debris, while thick liquid layers have the added benefit of protecting structures from fusion neutrons thereby significantly reducing the radiation damage and activation. The use of thick liquid walls is predicted to 1) reduce the cost of electricity by avoiding the cost and down time of changing damaged structures, and 2) reduce the cost of development by avoiding the cost of developing a new, low-activation material. Various schemes have been proposed to assure chamber clearing and renewal of the protective features at the required pulse rate. Representative chamber concepts are described, and key technical feasibility issues are identified for each class of chamber. Experimental activities (past, current, and proposed) to address these issues and technology research and development needs are discussed

  13. Design and performance of a straw tube drift chamber

    International Nuclear Information System (INIS)

    Oh, S.H.; Wesson, D.K.; Cooke, J.; Goshaw, A.T.; Robertson, W.J.; Walker, W.D.

    1991-01-01

    The design and performance of the straw drift chambers used in E735 is reported. The chambers are constructed from 2.5 cm radius aluminized mylar straw tubes with wall thickness less than 0.2 mm. Also, presented are the results of tests with 2 mm radius straw tubes. The small tube has a direct detector application at the Superconducting Super Collider. (orig.)

  14. Wire chambers: Trends and alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Regler, Meinhard

    1992-05-15

    The subtitle of this year's Vienna Wire Chamber Conference - 'Recent Trends and Alternative Techniques' - signalled that it covered a wide range of science and technology. While an opening Vienna talk by wire chamber pioneer Georges Charpak many years ago began 'Les funerailles des chambres a fils (the burial of wire chambers)', the contrary feeling this year was that wire chambers are very much alive!.

  15. Using the Nova target chamber for high-yield targets

    International Nuclear Information System (INIS)

    Pitts, J.H.

    1987-01-01

    The existing 2.2-m-radius Nova aluminum target chamber, coated and lined with boron-seeded carbon shields, is proposed for use with 1000-MJ-yield targets in the next laser facility. The laser beam and diagnostic holes in the target chamber are left open and the desired 10 -2 Torr vacuum is maintained both inside and outside the target chamber; a larger target chamber room is the vacuum barrier to the atmosphere. The hole area available is three times that necessary to maintain a maximum fluence below 12 J/cm 2 on optics placed at a radius of 10 m. Maximum stress in the target chamber wall is 73 MPa, which complies with the intent of the ASME Pressure Vessel Code. However, shock waves passing through the inner carbon shield could cause it to comminute. We propose tests and analyses to ensure that the inner carbon shield survives the environment. 13 refs

  16. DELPHI Barrel Muon Chamber Module

    CERN Multimedia

    1989-01-01

    The module was used as part of the muon identification system on the barrel of the DELPHI detector at LEP, and was in active use from 1989 to 2000. The module consists of 7 individual muons chambers arranged in 2 layers. Chambers in the upper layer are staggered by half a chamber width with respect to the lower layer. Each individual chamber is a drift chamber consisting of an anode wire, 47 microns in diameter, and a wrapped copper delay line. Each chamber provided 3 signal for each muon passing through the chamber, from which a 3D space-point could be reconstructed.

  17. Radon diffusion chamber

    International Nuclear Information System (INIS)

    Pretzsch, G.; Boerner, E.; Lehmann, R.; Sarenio, O.

    1986-01-01

    The invention relates to the detection of radioactive gases emitting alpha particles like radon, thoron and their alpha-decaying daughters by means of a diffusion chamber with a passive detector, preferably with a solid state track detector. In the chamber above and towards the detector there is a single metallized electret with negative polarity. The distance between electret and detector corresponds to the range of the alpha particles of radon daughters in air at the most. The electret collects the positively charged daughters and functions as surface source. The electret increases the sensitivity by the factor 4

  18. The Honeycomb Strip Chamber

    International Nuclear Information System (INIS)

    Graaf, Harry van der; Buskens, Joop; Rewiersma, Paul; Koenig, Adriaan; Wijnen, Thei

    1991-06-01

    The Honeycomb Strip Chamber (HSC) is a new position sensitive detector. It consists of a stack of folded foils, forming a rigid honeycomb structure. In the centre of each hexagonal cell a wire is strung. Conducting strips on the foils, perpendicular to the wires, pick up the induced avalanche charge. Test results of a prototype show that processing the signals form three adjacent strips nearest to the track gives a spatial resolution better than 64 μm for perpendicular incident tracks. The chamber performance is only slightly affected by a magnetic field. (author). 25 refs.; 21 figs

  19. Multiple chamber ionization detector

    International Nuclear Information System (INIS)

    Solomon, E.E.

    1982-01-01

    An ionization smoke detector employs a single radiation source in a construction comprising at least two chambers with a center or node electrode. The radioactive source is associated with this central electrode, and its positioning may be adjusted relative to the electrode to alter the proportion of the source that protrudes into each chamber. The source may also be mounted in the plane of the central electrode, and positioned relative to the center of the electrode. The central electrode or source may be made tiltable relative to the body of the detector

  20. Charpak hemispherical wire chamber

    CERN Multimedia

    1970-01-01

    pieces. Mesures are of the largest one. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  1. micro strip gas chamber

    CERN Multimedia

    1998-01-01

    About 16 000 Micro Strip Gas Chambers like this one will be used in the CMS tracking detector. They will measure the tracks of charged particles to a hundredth of a millimetre precision in the region near the collision point where the density of particles is very high. Each chamber is filled with a gas mixture of argon and dimethyl ether. Charged particles passing through ionise the gas, knocking out electrons which are collected on the aluminium strips visible under the microscope. Such detectors are being used in radiography. They give higher resolution imaging and reduce the required dose of radiation.

  2. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how wall...

  3. LEP vacuum chamber, prototype

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  4. Heavy liquid bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1965-01-01

    The CERN Heavy liquid bubble chamber being installed in the north experimental hall at the PS. On the left, the 1180 litre body; in the centre the magnet, which can produce a field of 26 800 gauss; on the right the expansion mechanism.

  5. The KLOE drift chamber

    International Nuclear Information System (INIS)

    Ferrari, A.

    2002-01-01

    The design and construction of the large drift chamber of the KLOE experiment is presented. The track reconstruction is described, together with the calibration method and the monitoring systems. The stability of operation and the performance are studied with samples of e + e - , K S K L and K + K - events

  6. Drift chamber detectors

    International Nuclear Information System (INIS)

    Duran, I.; Martinez Laso, L.

    1989-01-01

    A review of High Energy Physics detectors based on drift chambers is presented. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysied, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author)

  7. Drift Chambers detectors

    International Nuclear Information System (INIS)

    Duran, I.; Martinez laso, L.

    1989-01-01

    We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs

  8. OPAL Muon Chamber

    CERN Multimedia

    OPAL was one of the 4 experiments installed at the LEP particle accelerator from 1989 to 2000. This is a slice of the outermost layer of OPAL : the muon chambers. This outside layer detects particles which are not stopped by the previous layers. These are mostly muons.

  9. Improvements in ionization chambers

    International Nuclear Information System (INIS)

    Whetten, N.R.; Zubal, C.

    1980-01-01

    A method of reducing mechanical vibrations transmitted to the parallel plate electrodes of ionization chamber x-ray detectors, commonly used in computerized x-ray axial tomography systems, is described. The metal plate cathodes and anodes are mounted in the ionizable gas on dielectric sheet insulators consisting of a composite of silicone resin and glass fibres. (UK)

  10. LEP Vacuum Chamber

    CERN Multimedia

    1983-01-01

    This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

  11. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

    Would the person who borrowed the large bubble chamber lens from the Microcosm workshops on the ISR please return it. This is a much used piece from our object archives. If anybody has any information about the whereabouts of this object, please contact Emma.Sanders@cern.ch Thank you

  12. Review of straw chambers

    International Nuclear Information System (INIS)

    Toki, W.H.

    1990-03-01

    This is a review of straw chambers used in the HRS, MAC, Mark III, CLEO, AMY, and TPC e + e - experiments. The straws are 6--8 mm in diameter, operate at 1--4 atmospheres and obtain resolutions of 45--100 microns. The designs and constructions are summarized and possible improvements discussed

  13. Wire chamber conference

    International Nuclear Information System (INIS)

    Bartl, W.; Neuhofer, G.; Regler, M.

    1986-02-01

    This booklet contains program and the abstracts of the papers presented at the conference, most of them dealing with performance testing of various types of wire chambers. The publication of proceedings is planned as a special issue of 'Nuclear instruments and methods' later on. All abstracts are in English. An author index for the book of abstracts is given. (A.N.)

  14. Conceptual design of the fast ignition laser fusion power plant (KOYO-Fast). 6. Design of chamber and reactor system

    International Nuclear Information System (INIS)

    Kozaki, Yasuji; Norimatsu, Takayoshi; Furukawa, Hiroyuki; Hayashi, Takumi; Souman, Yoshihito; Nishikawa, Masabumi; Tomabechi, Ken

    2007-01-01

    A conceptual design of the reactor chamber system with LiPb liquid wall based on the fast ignition cone target design and the related reactor systems with exhaust system, laser beam shutter, blanket and cooling system are summarized. The multi overflow fall method was investigated as the structure of chamber and repeating 4 Hz pulse potential. The ablation depth of LiPb liquid wall was estimated and the conditions of repeat of operation were evaluated. The basic design of chamber, selection and conditions of liquid wall chamber, recycle type multi overflow fall (MOF) wall, LiPb two layers blanket structure, basic specification of reactor system, laser beam line shutter, design of chamber exhaust system, cooling system, tritium recovery system, power plant total design and arrangement of chamber and laser beam, and issues are stated. (S.Y.)

  15. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how walls...... have encouraged architectural thinking of enclosure, materiality, construction and inhabitation in architectural history, the paper’s aim is to define new directions for the integration of LEDs in walls, challenging the thinking of inhabitation and program. This paper introduces the notion...... of “ambiguous walls” as a more “critical” approach to design [1]. The concept of ambiguous walls refers to the diffuse status a lumious and possibly responsive wall will have. Instead of confining it can open up. Instead of having a static appearance, it becomes a context over time. Instead of being hard...

  16. HYLIFE-II reactor chamber mechanical design

    International Nuclear Information System (INIS)

    House, P.A.

    1992-01-01

    Mechanical design features of the reactor chamber for the HYLIFE-11 inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams are used for shielding and blast protection. The system is designed for an 8 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (20 m/s) salt streams and also recover up to half of the dynamic head

  17. Silicon-based sleeve devices for chemical reactions

    Science.gov (United States)

    Northrup, M. Allen; Mariella, Jr., Raymond P.; Carrano, Anthony V.; Balch, Joseph W.

    1996-01-01

    A silicon-based sleeve type chemical reaction chamber that combines heaters, such as doped polysilicon for heating, and bulk silicon for convection cooling. The reaction chamber combines a critical ratio of silicon and silicon nitride to the volume of material to be heated (e.g., a liquid) in order to provide uniform heating, yet low power requirements. The reaction chamber will also allow the introduction of a secondary tube (e.g., plastic) into the reaction sleeve that contains the reaction mixture thereby alleviating any potential materials incompatibility issues. The reaction chamber may be utilized in any chemical reaction system for synthesis or processing of organic, inorganic, or biochemical reactions, such as the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction, which are examples of a synthetic, thermal-cycling-based reaction. The reaction chamber may also be used in synthesis instruments, particularly those for DNA amplification and synthesis.

  18. Deployment and testing of a second prototype expandable surgical chamber in microgravity

    Science.gov (United States)

    Markham, Sanford M.; Rock, John A.

    1991-01-01

    During microgravity exposure, two separate expandable surgical chambers were tested. Both chambers had been modified to fit the microgravity work station without extending over the sides of the table. Both chambers were attached to a portable laminar flow generator which served two purposes: to keep the chambers expanded during use; and to provide an operative area environment free of contamination. During the tests, the chambers were placed on various parts of a total body moulage to simulate management of several types of trauma. The tests consisted of cleansing contusions, debridement of burns, and suturing of lacerations. Also, indigo carmine dye was deliberately injected into the chamber during the tests to determine the ease of cleansing the chamber walls after contamination by escaping fluids. Upon completion of the tests, the expandable surgical chambers were deflated, folded, and placed in a flattened state back into their original containers for storage and later disposal. Results are briefly discussed.

  19. Multiwire proportional chamber development

    Science.gov (United States)

    Doolittle, R. F.; Pollvogt, U.; Eskovitz, A. J.

    1973-01-01

    The development of large area multiwire proportional chambers, to be used as high resolution spatial detectors in cosmic ray experiments is described. A readout system was developed which uses a directly coupled, lumped element delay-line whose characteristics are independent of the MWPC design. A complete analysis of the delay-line and the readout electronic system shows that a spatial resolution of about 0.1 mm can be reached with the MWPC operating in the strictly proportional region. This was confirmed by measurements with a small MWPC and Fe-55 X-rays. A simplified analysis was carried out to estimate the theoretical limit of spatial resolution due to delta-rays, spread of the discharge along the anode wire, and inclined trajectories. To calculate the gas gain of MWPC's of different geometrical configurations a method was developed which is based on the knowledge of the first Townsend coefficient of the chamber gas.

  20. Radial semiconductor drift chambers

    International Nuclear Information System (INIS)

    Rawlings, K.J.

    1987-01-01

    The conditions under which the energy resolution of a radial semiconductor drift chamber based detector system becomes dominated by the step noise from the detector dark current have been investigated. To minimise the drift chamber dark current attention should be paid to carrier generation at Si/SiO 2 interfaces. This consideration conflicts with the desire to reduce the signal risetime: a higher drift field for shorter signal pulses requires a larger area of SiO 2 . Calculations for the single shaping and pseudo Gaussian passive filters indicate that for the same degree of signal risetime sensitivity in a system dominated by the step noise from the detector dark current, the pseudo Gaussian filter gives only a 3% improvement in signal/noise and 12% improvement in rate capability compared with the single shaper performance. (orig.)

  1. Neutron-sensitive ionization chamber

    International Nuclear Information System (INIS)

    Mayer, W.

    1978-01-01

    The neutron-sensitive ionization chamber which is to be applied for BWRs consists of a cylindrical outer electrode, closed at the ends, and a concentrically arranged inner electrode. It is designed as a hollow tube and coated with uranium on the outside. The reaction space lies between the two electrodes. The electrical connection is obtained through a coaxial cable whose nickel helix is properly intorduced into the inner electrode made of titanium or nickel. The sheathing respectively external conductor of the cable has got the same diameter as the outer electrode and is butt-welded to it. Between the cable helix and the sheathing there is filled Al 2 O 3 powder. The reaction space is sealed against the cable by means of a little tube pushed over the internal conductor resp. the helix. It consists of Ni resp. Al 2 O 3 which is coated on the outside at first by a layer of Al 2 O 3 and a layer of Ni resp. by a metal layer on the inside and on the outside. (DG) [de

  2. Temperature uniformity in the CERN CLOUD chamber

    Directory of Open Access Journals (Sweden)

    A. Dias

    2017-12-01

    Full Text Available The CLOUD (Cosmics Leaving OUtdoor Droplets experiment at CERN (European Council for Nuclear Research investigates the nucleation and growth of aerosol particles under atmospheric conditions and their activation into cloud droplets. A key feature of the CLOUD experiment is precise control of the experimental parameters. Temperature uniformity and stability in the chamber are important since many of the processes under study are sensitive to temperature and also to contaminants that can be released from the stainless steel walls by upward temperature fluctuations. The air enclosed within the 26 m3 CLOUD chamber is equipped with several arrays (strings of high precision, fast-response thermometers to measure its temperature. Here we present a study of the air temperature uniformity inside the CLOUD chamber under various experimental conditions. Measurements were performed under calibration conditions and run conditions, which are distinguished by the flow rate of fresh air and trace gases entering the chamber at 20 and up to 210 L min−1, respectively. During steady-state calibration runs between −70 and +20 °C, the air temperature uniformity is better than ±0.06 °C in the radial direction and ±0.1 °C in the vertical direction. Larger non-uniformities are present during experimental runs, depending on the temperature control of the make-up air and trace gases (since some trace gases require elevated temperatures until injection into the chamber. The temperature stability is ±0.04 °C over periods of several hours during either calibration or steady-state run conditions. During rapid adiabatic expansions to activate cloud droplets and ice particles, the chamber walls are up to 10 °C warmer than the enclosed air. This results in temperature differences of ±1.5 °C in the vertical direction and ±1 °C in the horizontal direction, while the air returns to its equilibrium temperature with a time constant of about 200 s.

  3. Vienna Wire Chamber Conference

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    After those of 1978 and 1980, a third Wire Chamber Conference was held from 15-18 February in the Technical University of Vienna. Eight invited speakers covered the field from sophisticated applications in biology and medicine, via software, to the state of the art of gaseous detectors. In some forty other talks the speakers tackled in more detail the topics of gaseous detectors, calorimetry and associated electronics and software

  4. Wire chamber gases

    International Nuclear Information System (INIS)

    Va'vra, J.

    1992-04-01

    In this paper, we describe new developments in gas mixtures which have occurred during the last 3--4 years. In particular, we discuss new results on the measurement and modeling of electron drift parameters, the modeling of drift chamber resolution, measurements of primary ionization and the choice of gas for applications such as tracking, single electron detection, X-ray detection and visual imaging. In addition, new results are presented on photon feedback, breakdown and wire aging

  5. Wall Turbulence.

    Science.gov (United States)

    Hanratty, Thomas J.

    1980-01-01

    This paper gives an account of research on the structure of turbulence close to a solid boundary. Included is a method to study the flow close to the wall of a pipe without interferring with it. (Author/JN)

  6. Lifetime survivability of contaminated target-chamber optics

    International Nuclear Information System (INIS)

    Rainer, F.; Anderson, A.; Burnham, A.; Milam, D.; Turner, R.

    1996-11-01

    Target chambers used for Inertial Confinement Fusion (ICF) expose laser optics to a very hostile environment, not only from high-fluence laser irradiation but also x-ray irradiation and particulate debris from targets and chamber wall materials. Expendable debris shields provide the first line of defense to more costly optics upstream in the laser beam path to contaminants generated within the target chamber. However, the replacement of a large number of debris shields is also an expensive proposition so that extending their usable lifetime within the chamber is important. We have conducted tests to show that optics can both be cleaned and damaged by laser irradiation at 355 nm after being contaminated with potential chamber-wall materials such as B 4 C and Al 2 O 3 . Such optics can survive from one to hundreds of laser shots, depending on degree of contamination and laser fluence levels. Similarly, we have studied the survivability of optics that have been exposed to direct contamination from representative target materials irradiated in the target chamber. We have also studied the effects on optics that were not directly exposed to targets, yet received secondary exposure from the above directly-exposed samples

  7. Double chambered right ventricle

    International Nuclear Information System (INIS)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung

    1983-01-01

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure

  8. Double chambered right ventricle

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1983-12-15

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure.

  9. Argus drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Danilov, M; Nagovizin, V; Hasemann, H; Michel, E; Schmidt-Parzefall, W; Wurth, R; Kim, P

    1983-11-15

    The ARGUS detector came into operation at the DORIS-II e/sup +/s/sup -/ storage ring at the end of 1982. Its two meter long drift chamber contains 5940 sense and 24588 field wires organized in uniform 18x18.8 mm/sup 2/ drift cells filling the whole volume. These cells form 36 layers, 18 of which provide stereo views. Each sense wire is equipped with a single hit TDC and ADC for coordinate and dE/dx measurements. The chamber is operated with propane to improve momentum and dE/dx resolution. The drift chamber design and initial performance are presented. With a very crude space-time relation approximation and without all the necessary corrections applied a spatial resolution of about 200 ..mu..m was obtained for half of the drift cell volume. Further corrections should improve this result. An intrinsic dE/dx resolution of 4.2% and an actual resolution of 5% were obtained for cosmic muons and also for Bhabha scattered electrons. An actual dE/dx resolution of 5.6% was obtained for pions from e/sup +/e/sup -/ annihilation data with almost no track selection. A relativistic rise of 30% was observed in good agreement with theory. The long-term stability is still to be investigated.

  10. Argus target chamber

    International Nuclear Information System (INIS)

    Rienecker, F. Jr.; Glaros, S.S.; Kobierecki, M.

    1975-01-01

    A target chamber for application in the laser fusion program must satisfy some very basic requirements. (1) Provide a vacuum on the order of 10 -6 torr. (2) Support a microscopically small target in a fixed point in space and verify its location within 5 micrometers. (3) Contain an adjustable beam focusing system capable of delivering a number of laser beams onto the target simultaneously, both in time and space. (4) Provide access for diagnostics to evaluate the results of target irradiation. (5) Have flexibility to allow changes in targets, focusing optics and number of beams. The ARGUS laser which is now under construction at LLL will have a target chamber which meets these requirements in a simple economic manner. The chamber and auxiliary equipment are described, with reference to two double beam focusing systems; namely, lenses and ellipsoidal mirrors. Provision is made for future operation with four beams, using ellipsoidal mirrors for two-sided illumination and lens systems for tetragonal and tetrahedral irradiation

  11. Bench measurement of vacuum chamber impedances with wires

    International Nuclear Information System (INIS)

    Shafer, R.E.

    1979-01-01

    Particle beams travelling in an accelerator or storage ring vacuum chamber produce electric and magnetic fields which interact with the walls of the chamber. The induced wall currents in turn generate secondary fields which can interact with the beam, giving rise to both energy loss and other effects which can cause beam instability. In many simple geometries these effects can be calculated. In more complex geometries the calculations are difficult and very approximate. For this reason it is important that the effects be measured if possible prior to installation. As accelerators become larger and the number of vacuum chamber components more numerous, and as more severe beam intensity and stability requirements are placing lower limits on the longitudinal and transverse impedances, a less than adequate component will be more likely to limit machine performance

  12. USING 14 C METHODOLOGY IN SMOG CHAMBER RESEARCH

    Science.gov (United States)

    Smog chambers are large enclosures (~ 10-200 m3) that are used to perform laboratory simulations of atmospheric reactions. By dealing with simple systems in which the number of reactants is limited and the conditions are strictly controlled, insights on how reactions ...

  13. Wire chambers: Trends and alternatives

    International Nuclear Information System (INIS)

    Regler, Meinhard

    1992-01-01

    The subtitle of this year's Vienna Wire Chamber Conference - 'Recent Trends and Alternative Techniques' - signalled that it covered a wide range of science and technology. While an opening Vienna talk by wire chamber pioneer Georges Charpak many years ago began 'Les funerailles des chambres a fils (the burial of wire chambers)', the contrary feeling this year was that wire chambers are very much alive!

  14. A new plant chamber facility PLUS coupled to the atmospheric simulation chamber SAPHIR

    Science.gov (United States)

    Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

    2015-11-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been build and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees are mixed with synthetic air and are transferred to the SAPHIR chamber where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOC) can be studied in detail. In PLUS all important enviromental parameters (e.g. temperature, PAR, soil RH etc.) are well-controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leafes of the plants is constructed such that gases are exposed to FEP Teflon film and other Teflon surfaces only to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 LED panels which have an emission strength up to 800 μmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOC) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light and temperature dependent BVOC emissions are studied using six Quercus Ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus Ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental set up and the utility of the newly added plant chamber.

  15. A new plant chamber facility, PLUS, coupled to the atmosphere simulation chamber SAPHIR

    Science.gov (United States)

    Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

    2016-03-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been built and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow-through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees is mixed with synthetic air and transferred to the SAPHIR chamber, where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOCs) can be studied in detail. In PLUS all important environmental parameters (e.g., temperature, photosynthetically active radiation (PAR), soil relative humidity (RH)) are well controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leaves of the plants is constructed such that gases are exposed to only fluorinated ethylene propylene (FEP) Teflon film and other Teflon surfaces to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 light-emitting diode (LED) panels, which have an emission strength up to 800 µmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOCs) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light- and temperature- dependent BVOC emissions are studied using six Quercus ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental setup and the utility of the newly added plant chamber.

  16. Hygrothermal behavior for a clay brick wall

    Science.gov (United States)

    Allam, R.; Issaadi, N.; Belarbi, R.; El-Meligy, M.; Altahrany, A.

    2018-06-01

    In Egypt, the clay brick is the common building materials which are used. By studying clay brick walls behavior for the heat and moisture transfer, the efficient use of the clay brick can be reached. So, this research studies the hygrothermal transfer in this material by measuring the hygrothermal properties and performing experimental tests for a constructed clay brick wall. We present the model for the hygrothermal transfer in the clay brick which takes the temperature and the vapor pressure as driving potentials. In addition, this research compares the presented model with previous models. By constructing the clay brick wall between two climates chambers with different boundary conditions, we can validate the numerical model and analyze the hygrothermal transfer in the wall. The temperature and relative humidity profiles within the material are measured experimentally and determined numerically. The numerical and experimental results have a good convergence with 3.5% difference. The surface boundary conditions, the ground effect, the infiltration from the closed chambers and the material heterogeneity affects the results. Thermal transfer of the clay brick walls reaches the steady state very rapidly than the moisture transfer. That means the effect of using only the external brick wall in the building in hot climate without increase the thermal resistance for the wall, will add more energy losses in the clay brick walls buildings. Also, the behavior of the wall at the heat and mass transfer calls the three-dimensional analysis for the whole building to reach the real behavior.

  17. Hygrothermal behavior for a clay brick wall

    Science.gov (United States)

    Allam, R.; Issaadi, N.; Belarbi, R.; El-Meligy, M.; Altahrany, A.

    2018-01-01

    In Egypt, the clay brick is the common building materials which are used. By studying clay brick walls behavior for the heat and moisture transfer, the efficient use of the clay brick can be reached. So, this research studies the hygrothermal transfer in this material by measuring the hygrothermal properties and performing experimental tests for a constructed clay brick wall. We present the model for the hygrothermal transfer in the clay brick which takes the temperature and the vapor pressure as driving potentials. In addition, this research compares the presented model with previous models. By constructing the clay brick wall between two climates chambers with different boundary conditions, we can validate the numerical model and analyze the hygrothermal transfer in the wall. The temperature and relative humidity profiles within the material are measured experimentally and determined numerically. The numerical and experimental results have a good convergence with 3.5% difference. The surface boundary conditions, the ground effect, the infiltration from the closed chambers and the material heterogeneity affects the results. Thermal transfer of the clay brick walls reaches the steady state very rapidly than the moisture transfer. That means the effect of using only the external brick wall in the building in hot climate without increase the thermal resistance for the wall, will add more energy losses in the clay brick walls buildings. Also, the behavior of the wall at the heat and mass transfer calls the three-dimensional analysis for the whole building to reach the real behavior.

  18. Space shuttle maneuvering engine reusable thrust chamber program. Task 11: Low epsilon stability test report data dump

    Science.gov (United States)

    Pauckert, R. P.

    1974-01-01

    The stability characteristics of the like-doublet injector were defined over the range of OME chamber pressures and mixture ratios. This was accomplished by bomb testing the injector and cavity configurations in solid wall thrust chamber hardware typical of a flight contour with fuel heated to regenerative chamber outlet temperatures. It was found that stability in the 2600-2800 Hz region depends upon injector hydraulics and on chamber acoustics.

  19. Criteria for controlled atmosphere chambers

    International Nuclear Information System (INIS)

    Robinson, J.N.

    1980-03-01

    The criteria for design, construction, and operation of controlled atmosphere chambers intended for service at ORNL are presented. Classification of chambers, materials for construction, design criteria, design, controlled atmosphere chamber systems, and operating procedures are presented. ORNL Safety Manual Procedure 2.1; ORNL Health Physics Procedure Manual Appendix A-7; and Design of Viewing Windows are included in 3 appendices

  20. Determination of the distribution and reaction of polysaccharides in wood cell walls by the isotope tracer technique, 6: Selective radio-labeling of mannan in ginkgo (Ginkgo biloba)

    International Nuclear Information System (INIS)

    Imai, T.; Terashima, N.; Yasuda, S.

    1997-01-01

    D-Mannose-[2-H-3] and GDP (guanosine diphosphate)-D-mannose-[mannose-1-H-3] were administered to the shoots of ginkgo (Ginkgo biloba L.) tolabel mannan selectively in the cell walls. To suppress the incorporation of radioactivity into the lignin and cellulose, the precursors were administered in the presence of the inhibitor of phenylalanine ammonia-lyase (PAL): namely, L-alpha-aminooxy-beta-phenylpropionic acid (AOPP) and the inhibitor of glucan synthesis: namely, 2-deoxy-D-glucose (2-DG) and 2.6-dichlorobenzonitrile (2.6-DCB). When D-mannose-[2-H-3] was administered in the absence of the inhibitors, great radioactivities were found in the mannose and glucose obtained by sulfuric acid hydrolysis of the newly-formed xylem, and also in the vanillin obtained by nitrobenzene oxidation. These results indicate that the radioactivity was incorporated not only into mannan but also into cellulose and lignin. When D-mannose-[2-H-3] was administered in the presence of both AOPP and 2-DG, the radioactivities of vanillin and glucose were decreased but that of mannose was not decreased. These results indicate that the incorporations of radioactivities into lignin and cellulose were suppressed by the inhibitors, but the incorporation into mannan was not interfered with. The treatment with 2,6-DCB lessened the incorporations of radioactivity into vanillin, xylose, mannose, and glucose of the newly formed xylem considerably which indicated that 2,6-DCB disturbed the metabolic activities of the plant fatally. Consequently, the selective radiolabeling of mannan in ginkgo was achieved by the administration of D-mannose-[2-H-3], in the presence of both AOPP and 2-DG, toa growing stem. In the case of GDP-D-mannose-[mannose-1-H-3], the radioactivity incorporated into the newly-formed xylem was very little, and the selectivity in labeling and the effects of the inhibitors were not clear

  1. In-situ testing of aircraft and satellites using a transportable reverberation chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2009-01-01

    A transportable reverberation chamber with vibrating walls to create high field strength has been developed, called Vibrating Intrinsic Reverberation Chamber (VIRC). It creates a statistically uniform electromagnetic field without the use of a rotating mode stirrer, resulting in a better homogeneity

  2. Design of a new multi-phase experimental simulation chamber for atmospheric photosmog, aerosol and cloud chemistry research

    Directory of Open Access Journals (Sweden)

    J. Wang

    2011-11-01

    Full Text Available A new simulation chamber has been built at the Interuniversitary Laboratory of Atmospheric Systems (LISA. The CESAM chamber (French acronym for Experimental Multiphasic Atmospheric Simulation Chamber is designed to allow research in multiphase atmospheric (photo- chemistry which involves both gas phase and condensed phase processes including aerosol and cloud chemistry. CESAM has the potential to carry out variable temperature and pressure experiments under a very realistic artificial solar irradiation. It consists of a 4.2 m3 stainless steel vessel equipped with three high pressure xenon arc lamps which provides a controlled and steady environment. Initial characterization results, all carried out at 290–297 K under dry conditions, concerning lighting homogeneity, mixing efficiency, ozone lifetime, radical sources, NOy wall reactivity, particle loss rates, background PM, aerosol formation and cloud generation are given. Photolysis frequencies of NO2 and O3 related to chamber radiation system were found equal to (4.2 × 10−3 s−1 for JNO2 and (1.4 × 10−5 s−1 for JO1D which is comparable to the solar radiation in the boundary layer. An auxiliary mechanism describing NOy wall reactions has been developed. Its inclusion in the Master Chemical Mechanism allowed us to adequately model the results of experiments on the photo-oxidation of propene-NOx-Air mixtures. Aerosol yields for the α-pinene + O3 system chosen as a reference were determined and found in good agreement with previous studies. Particle lifetime in the chamber ranges from 10 h to 4 days depending on particle size distribution which indicates that the chamber can provide high quality data on aerosol aging processes and their effects. Being evacuable, it is possible to generate in this new chamber

  3. Technical note: drifting versus anchored flux chambers for measuring greenhouse gas emissions from running waters

    Science.gov (United States)

    Lorke, A.; Bodmer, P.; Noss, C.; Alshboul, Z.; Koschorreck, M.; Somlai-Haase, C.; Bastviken, D.; Flury, S.; McGinnis, D. F.; Maeck, A.; Müller, D.; Premke, K.

    2015-12-01

    Stream networks have recently been discovered to be major but poorly constrained natural greenhouse gas (GHG) sources. A fundamental problem is that several measurement approaches have been used without cross-comparisons. Flux chambers represent a potentially powerful methodological approach if robust and reliable ways to use chambers on running water can be defined. Here we compare the use of anchored and freely drifting chambers on various streams with different flow velocities. The study clearly shows that (1) anchored chambers enhance turbulence under the chambers and thus elevate fluxes, (2) drifting chambers have a very small impact on the water turbulence under the chamber and thus generate more reliable fluxes, (3) the bias of the anchored chambers greatly depends on chamber design and sampling conditions, and (4) there is a promising method to reduce the bias from anchored chambers by using a flexible plastic foil collar to seal the chambers to the water surface, rather than having rigid chamber walls penetrating into the water. Altogether, these results provide novel guidance on how to apply flux chambers in running water, which will have important consequences for measurements to constrain the global GHG balances.

  4. DEVELOPMENT OF TITANIUM NITRIDE COATING FOR SNS RING VACUUM CHAMBERS

    International Nuclear Information System (INIS)

    HE, P.; HSEUH, H.C.; MAPES, M.; TODD, R.; WEISS, D.

    2001-01-01

    The inner surface of the ring vacuum chambers of the US Spallation Neutron Source (SNS) will be coated with ∼100 nm of Titanium Nitride (TiN). This is to minimize the secondary electron yield (SEY) from the chamber wall, and thus avoid the so-called e-p instability caused by electron multipacting as observed in a few high-intensity proton storage rings. Both DC sputtering and DC-magnetron sputtering were conducted in a test chamber of relevant geometry to SNS ring vacuum chambers. Auger Electron Spectroscopy (AES) and Rutherford Back Scattering (RBS) were used to analyze the coatings for thickness, stoichiometry and impurity. Excellent results were obtained with magnetron sputtering. The development of the parameters for the coating process and the surface analysis results are presented

  5. The Impedance of Multi-layer Vacuum Chambers

    CERN Document Server

    Vos, L

    2003-01-01

    Many components of the LHC vacuum chamber have multi-layered walls : the copper coated cold beam screen, the titanium coated ceramic chamber of the dump kickers, the ceramic chamber of the injection kickers coated with copper stripes, only to name a few. Theories and computer programs are available for some time already to evaluate the impedance of these elements. Nevertheless, the algorithm developed in this paper is more convenient in its application and has been used extensively in the design phase of multi-layer LHC vacuum chamber elements. It is based on classical transmission line theory. Closed expressions are derived for simple layer configurations, while beam pipes involving many layers demand a chain calculation. The algorithm has been tested with a number of published examples and was verified with experimental data as well.

  6. Numerical analysis of whole-body cryotherapy chamber design improvement

    Science.gov (United States)

    Yerezhep, D.; Tukmakova, A. S.; Fomin, V. E.; Masalimov, A.; Asach, A. V.; Novotelnova, A. V.; Baranov, A. Yu

    2018-05-01

    Whole body cryotherapy is a state-of-the-art method that uses cold for treatment and prevention of diseases. The process implies the impact of cryogenic gas on a human body that implements in a special cryochamber. The temperature field in the chamber is of great importance since local integument over-cooling may occur. Numerical simulation of WBC has been carried out. Chamber design modification has been proposed in order to increase the uniformity of the internal temperature field. The results have been compared with the ones obtained for a standard chamber design. The value of temperature gradient formed in the chamber containing curved wall with certain height has been decreased almost twice in comparison with the results obtained for the standard design. The modification proposed may increase both safety and comfort of cryotherapy.

  7. Synthesis and characterization of Pd@M(x)Cu(1-x) (M = Au, Pd, and Pt) nanocages with porous walls and a yolk-shell structure through galvanic replacement reactions.

    Science.gov (United States)

    Xie, Shuifen; Jin, Mingshang; Tao, Jing; Wang, Yucai; Xie, Zhaoxiong; Zhu, Yimei; Xia, Younan

    2012-11-19

    This paper describes the synthesis of Pd@M(x)Cu(1-x) (M = Au, Pd, and Pt) nanocages with a yolk-shell structure through galvanic replacement reactions that involve Pd@Cu core-shell nanocubes as sacrificial templates and ethylene glycol as the solvent. Compared with the most commonly used templates based on Ag, Cu offers a much lower reduction potential (0.34 versus 0.80 V), making the galvanic reaction more easily to conduct, even at room temperature. Our structural and compositional characterizations indicated that the products were hollow inside, and each one of them contained porous M-Cu alloy walls and a Pd cube in the interior. For the Pd@Au(x)Cu(1-x) yolk-shell nanocages, they displayed broad extinction peaks extending from the visible to the near-IR region. Our mechanistic study revealed that the dissolution of the Cu shell preferred to start from the slightly truncated corners and then progressed toward the interior, because the Cu {100} side faces were protected by a surface capping layer of hexadecylamine. This galvanic approach can also be extended to generating other hollow metal nanostructures by using different combinations of Cu nanostructures and salt precursors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Nuclear design considerations for Z-IFE chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W.R. [Lawrence Livermore National Laboratory, P.O. Box 808, L-641, Livermore, CA 94551 (United States)]. E-mail: meier5@llnl.gov; Schmitt, R.C. [Bettis Atomic Power Laboratory, Pittsburgh, PA 15203 (United States); Abbott, R.P. [Lawrence Livermore National Laboratory, P.O. Box 808, L-641, Livermore, CA 94551 (United States); Latkowski, J.F. [Lawrence Livermore National Laboratory, P.O. Box 808, L-641, Livermore, CA 94551 (United States); Reyes, S. [Lawrence Livermore National Laboratory, P.O. Box 808, L-641, Livermore, CA 94551 (United States)

    2006-02-15

    Z-pinch driven IFE (Z-IFE) requires the design of a repetitive target insertion system that allows coupling of the pulsed power to the target with adequate standoff, and a chamber that can withstand blast and radiation effects from large yield targets. The present strategy for Z-IFE is to use high yield targets ({approx}2-3 GJ/shot), low repetition rate per chamber ({approx}0.1 Hz), and 10 chambers per power plant. In this study, we propose an alternative power plant configuration that uses very high yield targets (20 GJ/shot) in a single chamber operating at 0.1 Hz. A thick-liquid-wall chamber is proposed to absorb the target emission (X-rays, debris and neutrons) and mitigate the blast effects on the chamber wall. The target is attached to the end of a conical shaped recyclable transmission line (RTL) made from a solid coolant (e.g., frozen flibe), or a material that is easily separable from the coolant (e.g., steel). The RTL/target assembly is inserted through a single opening at the top of the chamber for each shot. This study looks at the RTL material choice from a safety and environmental point of view. Materials were assessed according to waste disposal rating (WDR) and contact dose rate (CDR). Neutronics calculations, using the TART2002 Monte Carlo code from Lawrence Livermore National Laboratory (LLNL), were performed for the RTL and Z-IFE chamber, and key results reported here.

  9. Review of wire chamber aging

    International Nuclear Information System (INIS)

    Va'Vra, J.

    1986-02-01

    This paper makes an overview of the wire chamber aging problems as a function of various chamber design parameters. It emphasizes the chemistry point of view and many examples are drawn from the plasma chemistry field as a guidance for a possible effort in the wire chamber field. The paper emphasizes the necessity of variable tuning, the importance of purity of the wire chamber environment, as well as it provides a practical list of presently known recommendations. In addition, several models of the wire chamber aging are qualitatively discussed. The paper is based on a summary talk given at the Wire Chamber Aging Workshop held at LBL, Berkeley on January 16-17, 1986. Presented also at Wire Chamber Conference, Vienna, February 25-28, 1986. 74 refs., 18 figs., 11 tabs

  10. Space plasma simulation chamber

    International Nuclear Information System (INIS)

    1986-01-01

    Scientific results of experiments and tests of instruments performed with the Space Plasma Simulation Chamber and its facility are reviewed in the following six categories. 1. Tests of instruments on board rockets, satellites and balloons. 2. Plasma wave experiments. 3. Measurements of plasma particles. 4. Optical measurements. 5. Plasma production. 6. Space plasms simulations. This facility has been managed under Laboratory Space Plasma Comittee since 1969 and used by scientists in cooperative programs with universities and institutes all over country. A list of publications is attached. (author)

  11. Stability of Streamer Chamber

    Science.gov (United States)

    Wada, Toshiaki; Ogawa, Masato; Takahashi, Kaoru; Sugiyama, Tsunetoshi; Kobayashi, Shigeharu; Kohno, Hirobumi

    1982-08-01

    The quality of tracks obtained from a streamer chamber is studied through the measurement of the streamer brightness. The stability of streamer tracks depends on the value of the high voltage applied and its shape. By using a single conical-type spark gap as the pulse shaper, stable brightness of the streamer tracks is attained. The data on the streamer brightness are compared with the result by Bulos et al. and it is found that the brightness is more strongly affected by field parameters than in their result.

  12. Stability of streamer chamber

    International Nuclear Information System (INIS)

    Wada, Toshiaki; Ogawa, Masato; Takahashi, Kaoru; Sugiyama, Tsunetoshi; Kobayashi, Shigeharu; Kohno, Hirobumi.

    1982-01-01

    The quality of tracks obtained from a streamer chamber is studied through the measurement of the streamer brightness. The stability of streamer tracks depends on the value of the high voltage applied and its shape. By using a single conical-type spark gap as the pulse shaper, stable brightness of the streamer tracks is attained. The data on the streamer brightness are compared with the result by Bulos et al. and it is found that the brightness is more strongly affected by field parameters than in their result. (author)

  13. Consistent HYLIFE wall design that withstands transient loading conditions

    International Nuclear Information System (INIS)

    Pitts, J.H.

    1980-10-01

    The design for a first structural wall (FSW) promises to satisfy the impact and thermal stress loads for the 30-year lifetime anticipated for the HYLIFE reaction chamber. The FSW is a 50-mm-thick cylindrical plate that is 10 m in diameter; it can withstand a rapidly varying liquid metal impact stress up to a peak of 60 MPa, combined with slowly varying thermal stresses up to 86 MPa. We selected 2 1/4 Cr-1 Mo ferritic steel as the structural material because it has adequate fatigue properties and yield strength at the peak operating temperature of 810 0 K, is compatible with liquid lithium, and has good neutron activation characteristics

  14. Use of a streamer chamber for low energy nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Van Bibber, K.; Pang, W.; Avery, M.; Bloemhof, E.

    1979-10-01

    A small streamer chamber has been implemented for low energy heavy ion reaction studies at the LBL 88-inch cyclotron. The response of the chamber to light and heavy ions below 35 MeV/nucleon has been examined. The limited sensitivity of light output as a function of ionization works to advantage in recording a wide variety of tracks in the same photograph whose energy loss may vary considerably. Furthermore, as gas targets are attractive for several reasons, we have investigated the suitability of Ar and Xe for use in streamer chambers.

  15. Use of a streamer chamber for low energy nuclear physics

    International Nuclear Information System (INIS)

    Van Bibber, K.; Pang, W.; Avery, M.; Bloemhof, E.

    1979-10-01

    A small streamer chamber has been implemented for low energy heavy ion reaction studies at the LBL 88-inch cyclotron. The response of the chamber to light and heavy ions below 35 MeV/nucleon has been examined. The limited sensitivity of light output as a function of ionization works to advantage in recording a wide variety of tracks in the same photograph whose energy loss may vary considerably. Furthermore, as gas targets are attractive for several reasons, we have investigated the suitability of Ar and Xe for use in streamer chambers

  16. Council Chamber exhibition

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    To complete the revamp of CERN’s Council Chamber, a new exhibition is being installed just in time for the June Council meetings.   Panels will showcase highlights of CERN’s history, using some of the content prepared for the exhibitions marking 50 years of the PS, which were displayed in the main building last November. The previous photo exhibition in the Council Chamber stopped at the 1970s. To avoid the new panels becoming quickly out of date, photos are grouped together around specific infrastructures, rather than following a classic time-line. “We have put the focus on the accelerators – the world-class facilities that CERN has been offering researchers over the years, from the well-known large colliders to the lesser-known smaller facilities,” says Emma Sanders, who worked on the content. The new exhibition will be featured in a future issue of the Bulletin with photos and an interview with Fabienne Marcastel, designer of the exhibit...

  17. Cardiac chamber scintiscanning

    International Nuclear Information System (INIS)

    Goretzki, G.

    1981-01-01

    The two methods of cardiac chamber scintiscanning, i.e. 'first pass' and 'ECG-triggered' examinations, are explained and compared. Two tables indicate the most significant radiation doses of the applied radio tracers, i.e. 99m-Tc-pertechnetate and 99m-Tc-HSA, to which a patient is exposed. These averaged values are calculated from various data given in specialised literature. On the basis of data given in literature, an effective half-life of approximately 5 hours in the intravascular space was calculated for the erythrocytes labelled with technetium 99m. On this basis, the radiation doses for the patients due to 99m-Tc-labelled erythrocytes are estimated. The advantages and disadvantages of the two methods applied for cardiac chamber scintiscanning are put into contrast and compared with the advantages and disadvantages of the quantitative X-ray cardiography of the left heart. The still existing problems connected with the assessment of ECG-triggered images are discussed in detail. The author performed investigations of his own, which concerned the above-mentioned problems. (orig./MG) [de

  18. Conceptual design of low activation target chamber and components for the National Ignition Facility

    International Nuclear Information System (INIS)

    Streckert, H.H.; Schultz, K.R.; Sager, G.T.; Kantner, R.D.

    1996-01-01

    The baseline design for the target chamber and chamber components for the National Ignition Facility (NIF) consists of aluminum alloy structural material. Low activation composite chamber and components have important advantages including enhanced environmental and safety characteristics and improved accessibility due to reduced neutron-induced radioactivity. A low activation chamber can be fabricated from carbon fiber reinforced epoxy using thick wall laminate technology similar to submarine bow dome fabrication for the U.S. Navy. A risk assessment analysis indicates that a composite chamber has a reasonably high probability of success, but that an aluminum alloy chamber represents a lower risk. Use of low activation composite materials for several chamber components such as the final optics assemblies, the target positioner and inserter, the diagnostics manipulator tubes, and the optics beam tubes would offer an opportunity to make significant reductions in post-shot radiation dose rate with smaller, less immediate impact on the NIF design. 7 refs., 3 figs

  19. Absorbed dose calibration factors for parallel-plate chambers in high energy photon beams

    International Nuclear Information System (INIS)

    McEwen, M.R.; Duane, S.; Thomas, R.A.S.

    2002-01-01

    parallel-plate chambers, which is discussed below. The small difference (around 0.3%) between the NACP and Roos chambers at the highest photon energies is within the measurement uncertainties but may indicate a slight difference in chamber response. A number of chambers were recalibrated six months later to investigate chamber stability. It was found that the repeatability was generally better than 0.5% and the variations in time appear to be random. These differences are larger than for thimble chambers, where we have found stability at better than the 0.3% level over several years. Parallel-plate chambers in electron beams have also showed high stability (McEwen et al, 2001), which would indicate that parallel-plate chambers are sensitive to small variations in the beam quality of photon beams that do not affect thimble chambers. This data can also be used to derive relative wall correction factors for the Roos and NACP. Good agreement (within 0.3%) was found with previous data (Palm et al, 2000; Nystrom et al, 1993). These measurements would seem to confirm that p wall for the Roos chamber given in TRS-381 is too low by around 0.5%. Parallel-plate chambers can be calibrated in terms of absorbed dose to water, but with an uncertainty larger than for thimble chambers. Chamber stability also appears to be worse than for thimble chambers. Polarity corrections must always be measured and applied, as the polarity effect for a particular chamber is difficult to predict

  20. Microfabricated sleeve devices for chemical reactions

    Science.gov (United States)

    Northrup, M. Allen

    2003-01-01

    A silicon-based sleeve type chemical reaction chamber that combines heaters, such as doped polysilicon for heating, and bulk silicon for convection cooling. The reaction chamber combines a critical ratio of silicon and non-silicon based materials to provide the thermal properties desired. For example, the chamber may combine a critical ratio of silicon and silicon nitride to the volume of material to be heated (e.g., a liquid) in order to provide uniform heating, yet low power requirements. The reaction chamber will also allow the introduction of a secondary tube (e.g., plastic) into the reaction sleeve that contains the reaction mixture thereby alleviating any potential materials incompatibility issues. The reaction chamber may be utilized in any chemical reaction system for synthesis or processing of organic, inorganic, or biochemical reactions, such as the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction, which are examples of a synthetic, thermal-cycling-based reaction. The reaction chamber may also be used in synthesis instruments, particularly those for DNA amplification and synthesis.

  1. Reproducibility of the chamber scarification test

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner

    1996-01-01

    The chamber scarification test is a predictive human skin irritation test developed to rank the irritation potential of products and ingredients meant for repeated use on normal and diseased skin. 12 products or ingredients can be tested simultaneously on the forearm skin of each volunteer....... The test combines with the procedure scratching of the skin at each test site and subsequent closed patch tests with the products, repeated daily for 3 days. The test is performed on groups of human volunteers: a skin irritant substance or products is included in each test as a positive control...... high reproducibility of the test. Further, intra-individual variation in skin reaction to the 2 control products in 26 volunteers, who participated 2x, is shown, which supports the conclusion that the chamber scarification test is a useful short-term human skin irritation test with high reproducibility....

  2. Technical Note: Drifting vs. anchored flux chambers for measuring greenhouse gas emissions from running waters

    Science.gov (United States)

    Lorke, A.; Bodmer, P.; Noss, C.; Alshboul, Z.; Koschorreck, M.; Somlai, C.; Bastviken, D.; Flury, S.; McGinnis, D. F.; Maeck, A.; Müller, D.; Premke, K.

    2015-09-01

    Stream networks were recently discovered as major but poorly constrained natural greenhouse gas (GHG) sources. A fundamental problem is that several measurement approaches have been used without cross comparisons. Flux chambers represent a potentially powerful methodological approach if robust and reliable ways to use chambers on running water can be defined. Here we compare the use of anchored and freely drifting chambers on various streams having different flow velocities. The study clearly shows that (1) drifting chambers have a very small impact on the water turbulence under the chamber and thus generate more reliable fluxes, (2) anchored chambers enhance turbulence under the chambers and thus elevate fluxes, (3) the bias of the anchored chambers greatly depends on chamber design and sampling conditions, and (4) there is a promising method to reduce the bias from anchored chambers by using a flexible plastic foil seal to the water surface rather than having rigid chamber walls penetrating into the water. Altogether, these results provide novel guidance on how to apply flux chambers in running water, which will have important consequences for measurements to constrain the global GHG balances.

  3. Investigation of thermal and temporal responses of ionization chambers in radiation dosimetry.

    Science.gov (United States)

    AlMasri, Hussein; Funyu, Akira; Kakinohana, Yasumasa; Murayama, Sadayuki

    2012-07-01

    The ionization chamber is a primary dosimeter that is used in radiation dosimetry. Generally, the ion chamber response requires temperature/pressure correction according to the ideal gas law. However, this correction does not consider the thermal volume effect of chambers. The temporal and thermal volume effects of various chambers (CC01, CC13, NACP parallel-plate, PTW) with different wall and electrode materials have been studied in a water phantom. Measurements were done after heating the water with a suitable heating system, and chambers were submerged for a sufficient time to allow for temperature equilibrium. Temporal results show that all chambers equilibrate quickly in water. The equilibration time was between 3 and 5 min for all chambers. Thermal results show that all chambers expanded in response to heating except for the PTW, which contracted. This might be explained by the differences in the volumes of all chambers and also by the difference in wall material composition of PTW from the other chambers. It was found that the smallest chamber, CC01, showed the greatest expansion. The magnitude of the expansion was ~1, 0.8, and 0.9% for CC01, CC13, and parallel-plate chambers, respectively, in the temperature range of 295-320 K. The magnitude of the detected contraction was <0.3% for PTW in the same temperature range. For absolute dosimetry, it is necessary to make corrections for the ion chamber response, especially for small ion chambers like the CC01. Otherwise, room and water phantom temperatures should remain within a close range.

  4. Diogene pictorial drift chamber

    International Nuclear Information System (INIS)

    Gosset, J.

    1984-01-01

    A pictorial drift chamber, called DIOGENE, has been installed at Saturne in order to study central collisions of high energy heavy ions. It has been adapted from the JADE internal detector, with two major differences to be taken into account. First, the center-of-mass of these collisions is not identical to the laboratory reference frame. Second, the energy loss and the momentum ranges of the particles to be detected are different from the ones in JADE. It was also tried to keep the cost as small as possible, hence the choice of minimum size and minimum number of sensitive wires. Moreover the wire planes are shifted from the beam axis: this trick helps very much to quickly reject the bad tracks caused by the ambiguity of measuring drift distances (positive or negative) through times (always positive)

  5. Simulation of chamber experiments

    International Nuclear Information System (INIS)

    Ivanov, V.G.

    1981-01-01

    The description of the system of computer simulation of experiments conducted by means of track detectors with film data output is given. Considered is the principle of organization of computer model of the chamber experiment comprising the following stages: generation of events, generation of measurements, ge-- neration of scanning results, generation of distorbions, generated data calibration, filtration, events reconstruction, kinematic identification, total results tape formation, analysis of the results. Generation programs are formed as special RAM-files, where the RAM-file is the text of the program written in FORTRAN and divided into structural elements. All the programs are a ''part of the ''Hydra'' system. The system possibilities are considered on the base of the CDSC-6500 computer. The five-beam event generation, creation data structure for identification and calculation by the kinematic program take about 1s of CDC-6500 computer time [ru

  6. Nucleation in bubble chambers

    International Nuclear Information System (INIS)

    Harigel, G.G.

    1988-01-01

    Various sources and mechanisms for bubble formation in superheated liquids are discussed. Bubble chambers can be filled with a great variety of liquids, such as e.g. the cryogenic liquids hydrogen, deuterium, neon, neon/hydrogen mixtures, argon, nitrogen, argon/nitrogen mixtures, or the warm liquids propane and various Freon like Freon-13B1. The superheated state is normally achieved by a rapid movement of an expansion piston or membrane, but can also be produced by standing ultrasonic waves, shock waves, or putting liquids under tension. Bubble formation can be initiated by ionizing particles, by intense (laser) light, or on rough surfaces. The creation of embryonic bubbles is not completely understood, but the macroscopic growth and condensation can be calculated, allowing to estimate the dynamic heat load [fr

  7. Fusion technology development: first wall/blanket system and component testing in existing nuclear facilities

    International Nuclear Information System (INIS)

    Hsu, P.Y.S.; Bohn, T.S.; Deis, G.A.; Judd, J.L.; Longhurst, G.R.; Miller, L.G.; Millsap, D.A.; Scott, A.J.; Wessol, D.E.

    1980-12-01

    A novel concept to produce a reasonable simulation of a fusion first wall/blanket test environment employing an existing nuclear facility, the Engineering Test Reactor at the Idaho National Engineering Laboratory, is presented. Preliminary results show that an asymmetric, nuclear test environment with surface and volumetric heating rates similar to those expected in a fusion first wall/blanket or divertor chamber surface appears feasible. The proposed concept takes advantage of nuclear reactions within the annulus of an existing test space (15 cm in diameter and approximately 100 cm high) to provide an energy flux to the surface of a test module. The principal reaction considered involves 3 He in the annulus as follows: n + 3 He → p + t + 0.75 MeV. Bulk heating in the test module is accomplished by neutron thermalization, gamma heating, and absorption reactions involving 6 Li in the blanket breeding region. The concept can be extended to modified core configurations that will accommodate test modules of different sizes and types. It makes possible development testing of first wall/blanket systems and other fusion components on a scale and in ways not otherwise available until actual high-power fusion reactors are built

  8. Impact of beam transport method on chamber and driver design for heavy ion inertial fusion energy

    Energy Technology Data Exchange (ETDEWEB)

    Rose, D.V.; Welch, D.R.; Olson, C.L.; Yu, S.S.; Neff, S.; Sharp, W.M.

    2002-12-01

    In heavy ion inertial fusion energy systems, intense beams of ions must be transported from the exit of the final focus magnet system through the target chamber to hit millimeter spot sizes on the target. In this paper, we examine three different modes of beam propagation: neutralized ballistic transport, assisted pinched transport, and self-pinched transport. The status of our understanding of these three modes is summarized, and the constraints imposed by beam propagation upon the chamber environment, as well as their compatibility with various chamber and target concepts, are considered. We conclude that, on the basis of our present understanding, there is a reasonable range of parameter space where beams can propagate in thick-liquid wall, wetted-wall, and dry-wall chambers.

  9. Ionization chamber gradient effects in nonstandard beam configurations

    International Nuclear Information System (INIS)

    Bouchard, Hugo; Seuntjens, Jan; Carrier, Jean-Francois; Kawrakow, Iwan

    2009-01-01

    Purpose: For the purpose of nonstandard beam reference dosimetry, the current concept of reporting absorbed dose at a point in water located at a representative position in the chamber volume is investigated in detail. As new nonstandard beam reference dosimetry protocols are under development, an evaluation of the role played by the definition of point of measurement could lead to conceptual improvements prior to establishing measurement procedures. Methods: The present study uses the current definition of reporting absorbed dose to calculate ionization chamber perturbation factors for two cylindrical chamber models (Exradin A12 and A14) using the Monte Carlo method. The EGSnrc based user-code EGS lowbar chamber is used to calculate chamber dose responses of 14 IMRT beams chosen to cause considerable dose gradients over the chamber volume as previously used by Bouchard and Seuntjens [''Ionization chamber-based reference dosimetry of intensity modulated radiation beams,'' Med. Phys. 31(9), 2454-5465 (2004)]. Results: The study shows conclusively the relative importance of each physical effect involved in the nonstandard beam correction factors of 14 IMRT beams. Of all correction factors involved in the dosimetry of the beams studied, the gradient perturbation correction factor has the highest magnitude, on average, 11% higher compared to reference conditions for the Exradin A12 chamber and about 5% higher for the Extradin A14 chamber. Other perturbation correction factors (i.e., P wall , P stem , and P cel ) are, on average, less than 0.8% different from reference conditions for the chambers and beams studied. The current approach of reporting measured absorbed dose at a point in water coinciding with the location of the centroid of the chamber is the main factor responsible for large correction factors in nonstandard beam deliveries (e.g., intensity modulated radiation therapy) reported in literature. Conclusions: To reduce or eliminate the magnitude of

  10. Development of Aluminium Vacuum Chambers for the LHC Experiments at CERN

    CERN Document Server

    Gallilee, M; Costa-Pinto, P; Lepeule, P; Perez-Espinos, J; Marques Antunes Ferreira, L; Prever-Loiri, L; Sapountzis, A

    2014-01-01

    Beam losses may cause activation of vacuum chamber walls, in particular those of the Large Hadron Collider (LHC) experiments. For the High Luminosity (HL-LHC), the activation of such vacuum chambers will increase. It is therefore necessary to use a vacuum chamber material which interacts less with the circulating beam. While beryllium is reserved for the collision point, a good compromise between cost, availability and transparency is obtained with aluminium alloys; such materials are a preferred choice with respect to austenitic stainless steel. Manufacturing a thin-wall aluminium vacuum chamber presents several challenges as the material grade needs to be machinable, weldable, leak-tight for small thicknesses, and able to withstand heating to 250°C for extended periods of time. This paper presents some of the technical challenges during the manufacture of these vacuum chambers and the methods for overcoming production difficulties, including surface treatments and Non-Evaporable Getter (NEG) thin-film coat...

  11. One-dimensional flame instability and control of burning in fire-chamber

    Directory of Open Access Journals (Sweden)

    Victor E. Volkov

    2015-03-01

    Full Text Available The flame stability with regard to one-dimensional exponential perturbations both for the combustion in the fire-chamber and the flame propagating in closed tubes or chambers is investigated. It is proved that both stability and instability are possible for the combustion process. At the same time the one-dimensional flame instability is guaranteed near the front wall of the fire-chamber where the fuel supply is realized. Therefore the control of combustion in the fire-chamber leads to support of the flame at the maximum possible distance from the front wall of the fire-chamber to prevent the vibratory combustion or to diminish intensity of pulsations if these pulsations are inevitable.

  12. Development of X-Y multiwire proportional chamber (MWPC) for the magnetic spectrograph 'BIG KARL' of the Juelich cyclotron 'JULIC' and investigation of the reaction 12C(α,α1)12C with Eα=145 MeV

    International Nuclear Information System (INIS)

    Koehler, M.

    1978-07-01

    The paper reports on the concept and development of a spatial-resolution X-Y detector for the magnetic spectrograph BIG KARL, on test measurements on the 300 mm x 40 mm prototype with a 90 Sr β source, and on the first few in-beam measurements. The reaction 12 C(α,α') 12 C with Esub(α) = 145 MeV was investigated under extreme forward angles thetasub(LAB) = 6.0 0 to 1.5 0 . (orig./WL) 891 WL [de

  13. Structure and chemical composition changes of Pd-rod and reaction product collector irradiated by 10 MeV braking gamma quanta inside high pressure chamber filled with 2.5 kbar molecular hydrogen

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Wisniewski, R.

    2013-01-01

    A research of the elemental composition and surface structure of a Pd rod saturated with hydrogen and a brass collector of nuclear and chemical reaction products irradiated by 10 MeV braking gamma quanta in dense molecular hydrogen gas at 2.5 kbar pressure is carried out. The changes of the elemental composition and surface structure of the Pd rod and collector similar to analogous changes in the experiment carried out in dense gas deuterium are observed. Possible explanations of the firstly observed phenomenon are offered

  14. Determination and analysis of uptake of gaseous hydrogen peroxide by red spruce seedlings, determined by CSTR-type chamber experiments

    International Nuclear Information System (INIS)

    Claiborn, C.S.; Aneja, V.P.; Carbonell, R.G.

    1991-01-01

    In order to better understand the pathways for damage, the fate of gaseous hydrogen peroxide in red spruce needles was examined. The uptake of gaseous hydrogen peroxide by red spruce trees was determined from controlled exposure chamber experiments in which the chamber behaved as a Continuous Stirred Tank Reactor (CSTR). The results from these experiments were analyzed using a detailed transport model developed from fundamental principles, in order to determine the fate of hydrogen peroxide in the needles and characterize the exposure. The chamber was specially designed to accommodate highly reactive gases. All inner surfaces were Teflon-coated to minimize wall losses. Fluxes of hydrogen peroxide, carbon dioxide, and water vapor were determined. Both daytime and nighttime conditions were examined. Although other investigators have reported that the flux of other, less water-soluble pollutants to red spruce decreases at night when the stomata closes, the hydrogen peroxide flux did not exhibit this behavior. The results of these studies suggest that, at the concentrations observed in the atmosphere, hydrogen peroxide does not reach the inner, mesophyll tissues, but is lost in water condensing in the cuticular wax residing in the stomatal antechamber, above the stomata. The implications of the condensation in the stomatal antechamber and subsequent reactions occurring in this water for forest damage are discussed

  15. Numerical analysis of the thermo-fluid-dynamic field in the combustion chamber of an incinerator plant

    International Nuclear Information System (INIS)

    Costa, M.; Dell'Isola, M.; Massarotti, N.

    2009-01-01

    As the interest for energy recovery from waste incineration has increased over the years, concern for the impact such processes have on the environment has also grown. To reduce such an impact, the legislation enforced in Italy and Europe imposes important restrictions on the temperature of the exhausts in the combustion chamber, which must be kept above certain values depending on the type of waste that is being incinerated, for a given period of time. Such conditions can be rather difficult and certainly very expensive to monitor with acceptable accuracy. In this work, a numerical approach is presented for modelling waste combustion in a full scale incineration plant. Both solid and gas phase reactions are considered. Various modes of heat and mass transfer between the waste bed, the air and the combustion products are taken into account, as well as radiation from the combustion chamber walls and the combustion products. The temperature distribution in the combustion chamber is obtained considering either forced or mixed convection. It is therefore shown that neglecting buoyancy effects may lead to appreciable errors. Verification of the code performance is based on comparison with the results of an experimental campaign at a full scale plant in Italy.

  16. Enhancing chemical reactions

    Science.gov (United States)

    Morrey, John R.

    1978-01-01

    Methods of enhancing selected chemical reactions. The population of a selected high vibrational energy state of a reactant molecule is increased substantially above its population at thermal equilibrium by directing onto the molecule a beam of radiant energy from a laser having a combination of frequency and intensity selected to pump the selected energy state, and the reaction is carried out with the temperature, pressure, and concentrations of reactants maintained at a combination of values selected to optimize the reaction in preference to thermal degradation by transforming the absorbed energy into translational motion. The reaction temperature is selected to optimize the reaction. Typically a laser and a frequency doubler emit radiant energy at frequencies of .nu. and 2.nu. into an optical dye within an optical cavity capable of being tuned to a wanted frequency .delta. or a parametric oscillator comprising a non-centrosymmetric crystal having two indices of refraction, to emit radiant energy at the frequencies of .nu., 2.nu., and .delta. (and, with a parametric oscillator, also at 2.nu.-.delta.). Each unwanted frequency is filtered out, and each desired frequency is focused to the desired radiation flux within a reaction chamber and is reflected repeatedly through the chamber while reactants are fed into the chamber and reaction products are removed therefrom.

  17. Probing the influence of the center atom coordination structure in iron phthalocyanine multi-walled carbon nanotube-based oxygen reduction reaction catalysts by X-ray absorption fine structure spectroscopy

    Science.gov (United States)

    Peng, Yingxiang; Li, Zhipan; Xia, Dingguo; Zheng, Lirong; Liao, Yi; Li, Kai; Zuo, Xia

    2015-09-01

    Three different pentacoordinate iron phthalocyanine (FePc) electrocatalysts with an axial ligand (pyridyl group, Py) anchored to multi-walled carbon nanotubes (MWCNTs) are prepared by a microwave method as high performance composite electrocatalysts (FePc-Py/MWCNTs) for the oxygen reduction reaction (ORR). For comparison, tetracoordinate FePc electrocatalysts without an axial ligand anchored to MWCNTs (FePc/MWCNTs) are assembled in the same way. Ultraviolet-visible spectrophotometry (UV-Vis), Raman spectroscopy (RS), and high-resolution transmission electron microscopy (HRTEM) are used to characterize the obtained electrocatalysts. The electrocatalytic activity of the samples is measured by linear sweep voltammetry (LSV), and the onset potential of all of the FePc-Py/MWCNTs electrocatalysts is found to be more positive than that of their FePc/MWCNTs counterparts. X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) spectroscopy are employed to elucidate the relationship between molecular structure and electrocatalytic activity. XPS indicates that higher concentrations of Fe3+ and pyridine-type nitrogen play critical roles in determining the electrocatalytic ORR activity of the samples. XAFS spectroscopy reveals that the FePc-Py/MWCNTs electrocatalysts have a coordination geometry around Fe that is closer to the square pyramidal structure, a higher concentration of Fe3+, and a smaller phthalocyanine ring radius compared with those of FePc/MWCNTs.

  18. Ozone deposition velocities, reaction probabilities and product yields for green building materials

    Science.gov (United States)

    Lamble, S. P.; Corsi, R. L.; Morrison, G. C.

    2011-12-01

    Indoor surfaces can passively remove ozone that enters buildings, reducing occupant exposure without an energy penalty. However, reactions between ozone and building surfaces can generate and release aerosols and irritating and carcinogenic gases. To identify desirable indoor surfaces the deposition velocity, reaction probability and carbonyl product yields of building materials considered green (listed, recycled, sustainable, etc.) were quantified. Nineteen separate floor, wall or ceiling materials were tested in a 10 L, flow-through laboratory reaction chamber. Inlet ozone concentrations were maintained between 150 and 200 ppb (generally much lower in chamber air), relative humidity at 50%, temperature at 25 °C and exposure occurred over 24 h. Deposition velocities ranged from 0.25 m h -1 for a linoleum style flooring up to 8.2 m h -1 for a clay based paint; reaction probabilities ranged from 8.8 × 10 -7 to 6.9 × 10 -5 respectively. For all materials, product yields of C 1 thru C 12 saturated n-aldehydes, plus acetone ranged from undetectable to greater than 0.70 The most promising material was a clay wall plaster which exhibited a high deposition velocity (5.0 m h -1) and a low product yield (

  19. Space shuttle orbit maneuvering engine reusable thrust chamber program

    Science.gov (United States)

    Senneff, J. M.

    1975-01-01

    Reusable thrust chamber and injector concepts were evaluated for the space shuttle orbit maneuvering engine (OME). Parametric engine calculations were carried out by computer program for N2O4/amine, LOX/amine and LOX/hydrocarbon propellant combinations for engines incorporating regenerative cooled and insulated columbium thrust chambers. The calculation methods are described including the fuel vortex film cooling method of combustion gas temperature control, and performance prediction. A method of acceptance of a regeneratively cooled heat rejection reduction using a silicone oil additive was also demonstrated by heated tube heat transfer testing. Regeneratively cooled thrust chamber operation was also demonstrated where the injector was characterized for the OME application with a channel wall regenerative thrust chamber. Bomb stability testing of the demonstration chambers/injectors demonstrated recovery for the nominal design of acoustic cavities. Cavity geometry changes were also evaluated to assess their damping margin. Performance and combustion stability was demonstrated of the originally developed 10 inch diameter combustion pattern operating in an 8 inch diameter thrust chamber.

  20. Development of a time projection chamber for Crystal Ball at MAMI

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Oliver; Wolfes, Martin; Gradl, Wolfgang [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Collaboration: A2-Collaboration

    2014-07-01

    The Crystal Ball Collaboration uses energy tagged bremstrahlung photons produced from the MAMI electron beam to study photo-induced reactions on nucleons and nuclei. The Crystal Ball/TAPS 4π calorimeter setup is optimized for the detection of neutral final states. Charged particles are identified and measured by the inner detector system including a two layer MWPC. The increased rate of charged particles in current and future experiments exceeds the rate capability of these MWPCs. We are developing a small Time Projection Chamber with triple GEM readout meeting the stringent space requirements of the Crystal Ball experiment. This new tracking detector will feature higher rate capabilities and allows better track reconstruction. We are investigating the use of Carbon Fiber Reinforced Plastics (CFRP) to build light but strong chamber walls. First tests with carbon fiber prepregs show promising results. In addition we are using the PLUTO event generator to study the detector acceptance under our experiment conditions. Similar simulations are done to optimize the number and the shape of the readout pads. This poster gives an overview of the current status of the project and present the latest results.

  1. The little holographic bubble chambers

    International Nuclear Information System (INIS)

    Herve, A.

    1983-01-01

    The lifetime study of the charmed particles has readvanced the idea to use holography for the little fast-cycle bubble chambers. A pilot experiment has been realised in 1982 with a little bubble chamber filled up with freon-115. 40000 holograms have been recorded [fr

  2. ICF gamma-ray reaction history diagnostics

    International Nuclear Information System (INIS)

    Herrmann, H W; Young, C S; Mack, J M; Kim, Y H; McEvoy, A; Evans, S; Sedillo, T; Batha, S; Schmitt, M; Wilson, D C; Langenbrunner, J R; Malone, R; Kaufman, M I; Cox, B C; Frogget, B; Tunnell, T W; Miller, E K; Ali, Z A; Stoeffl, W; Horsfield, C J

    2010-01-01

    Reaction history measurements, such as nuclear bang time and burn width, are fundamental components of diagnosing ICF implosions and will be employed to help steer the National Ignition Facility (NIF) towards ignition. Fusion gammas provide a direct measure of nuclear interaction rate (unlike x-rays) without being compromised by Doppler spreading (unlike neutrons). Gas Cherenkov Detectors that convert fusion gamma rays to UV/visible Cherenkov photons for collection by fast optical recording systems have established their usefulness in illuminating ICF physics in several experimental campaigns at OMEGA. In particular, bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF. NIF Gamma Reaction History (GRH) diagnostics are being developed based on optimization of sensitivity, bandwidth, dynamic range, cost, and NIF-specific logistics, requirements and extreme radiation environment. Implementation will occur in two phases. The first phase consists of four channels mounted to the outside of the target chamber at ∼6 m from target chamber center (GRH-6m) coupled to ultra-fast photo-multiplier tubes (PMT). This system is intended to operate in the 10 13 -10 17 neutron yield range expected during the early THD campaign. It will have high enough bandwidth to provide accurate bang times and burn widths for the expected THD reaction histories (> 80 ps fwhm). Successful operation of the first GRH-6m channel has been demonstrated at OMEGA, allowing a verification of instrument sensitivity, timing and EMI/background suppression. The second phase will consist of several channels located just inside the target bay shield wall at 15 m from target chamber center (GRH-15m) with optical paths leading through the cement shield wall to well-shielded streak cameras and PMTs. This system is intended to operate in the 10 16 -10 20 yield range expected during the DT ignition campaign, providing higher temporal resolution

  3. ICF gamma-ray reaction history diagnostics

    Science.gov (United States)

    Herrmann, H. W.; Young, C. S.; Mack, J. M.; Kim, Y. H.; McEvoy, A.; Evans, S.; Sedillo, T.; Batha, S.; Schmitt, M.; Wilson, D. C.; Langenbrunner, J. R.; Malone, R.; Kaufman, M. I.; Cox, B. C.; Frogget, B.; Miller, E. K.; Ali, Z. A.; Tunnell, T. W.; Stoeffl, W.; Horsfield, C. J.; Rubery, M.

    2010-08-01

    Reaction history measurements, such as nuclear bang time and burn width, are fundamental components of diagnosing ICF implosions and will be employed to help steer the National Ignition Facility (NIF) towards ignition. Fusion gammas provide a direct measure of nuclear interaction rate (unlike x-rays) without being compromised by Doppler spreading (unlike neutrons). Gas Cherenkov Detectors that convert fusion gamma rays to UV/visible Cherenkov photons for collection by fast optical recording systems have established their usefulness in illuminating ICF physics in several experimental campaigns at OMEGA. In particular, bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF. NIF Gamma Reaction History (GRH) diagnostics are being developed based on optimization of sensitivity, bandwidth, dynamic range, cost, and NIF-specific logistics, requirements and extreme radiation environment. Implementation will occur in two phases. The first phase consists of four channels mounted to the outside of the target chamber at ~6 m from target chamber center (GRH-6m) coupled to ultra-fast photo-multiplier tubes (PMT). This system is intended to operate in the 1013-1017 neutron yield range expected during the early THD campaign. It will have high enough bandwidth to provide accurate bang times and burn widths for the expected THD reaction histories (> 80 ps fwhm). Successful operation of the first GRH-6m channel has been demonstrated at OMEGA, allowing a verification of instrument sensitivity, timing and EMI/background suppression. The second phase will consist of several channels located just inside the target bay shield wall at 15 m from target chamber center (GRH-15m) with optical paths leading through the cement shield wall to well-shielded streak cameras and PMTs. This system is intended to operate in the 1016-1020 yield range expected during the DT ignition campaign, providing higher temporal resolution for the

  4. National Ignition Facility Target Chamber

    International Nuclear Information System (INIS)

    Wavrik, R W; Cox, J R; Fleming, P J

    2000-01-01

    On June 11, 1999 the Department of Energy dedicated the single largest piece of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The ten (10) meter diameter aluminum target high vacuum chamber will serve as the working end of the largest laser in the world. The output of 192 laser beams will converge at the precise center of the chamber. The laser beams will enter the chamber in two by two arrays to illuminate 10 millimeter long gold cylinders called hohlraums enclosing 2 millimeter capsule containing deuterium, tritium and isotopes of hydrogen. The two isotopes will fuse, thereby creating temperatures and pressures resembling those found only inside stars and in detonated nuclear weapons, but on a minute scale. The NIF Project will serve as an essential facility to insure safety and reliability of our nation's nuclear arsenal as well as demonstrating inertial fusion's contribution to creating electrical power. The paper will discuss the requirements that had to be addressed during the design, fabrication and testing of the target chamber. A team from Sandia National Laboratories (SNL) and LLNL with input from industry performed the configuration and basic design of the target chamber. The method of fabrication and construction of the aluminum target chamber was devised by Pitt-Des Moines, Inc. (PDM). PDM also participated in the design of the chamber in areas such as the Target Chamber Realignment and Adjustment System, which would allow realignment of the sphere laser beams in the event of earth settlement or movement from a seismic event. During the fabrication of the target chamber the sphericity tolerances had to be addressed for the individual plates. Procedures were developed for forming, edge preparation and welding of individual plates. Construction plans were developed to allow the field construction of the target chamber to occur parallel to other NIF construction activities. This was

  5. The CLEO III drift chamber

    CERN Document Server

    Peterson, D; Briere, R A; Chen, G; Cronin-Hennessy, D; Csorna, S; Dickson, M; Dombrowski, S V; Ecklund, K M; Lyon, A; Marka, S; Meyer, T O; Patterson, J R; Sadoff, A; Thies, P; Thorndike, E H; Urner, D

    2002-01-01

    The CLEO group at the Cornell Electron Storage Ring has constructed and commissioned a new central drift chamber. With 9796 cells arranged in 47 layers ranging in radius from 13.2 to 79 cm, the new drift chamber has a smaller outer radius and fewer wires than the drift chamber it replaces, but allows the CLEO tracking system to have improved momentum resolution. Reduced scattering material in the chamber gas and in the inner skin separating the drift chamber from the silicon vertex detector provides a reduction of the multiple scattering component of the momentum resolution and an extension of the usable measurement length into the silicon. Momentum resolution is further improved through quality control in wire positioning and symmetry of the electric fields in the drift cells which have provided a reduction in the spatial resolution to 88 mu m (averaged over the full drift range).

  6. Ion chamber repairs in Bruce A

    International Nuclear Information System (INIS)

    Millard, J.; Edwards, T.; Kerker, J.; Pletch, R.; Edwards, T.

    2012-01-01

    This paper discusses identification and successful remediation of leakage of shield tank water on vertical and horizontal Ion Chambers in Bruce A. In doing so, it discusses real events moving from the initial investigation to understand the problem, through looking at options for solutions, and moving to site work and actual resolution.. In multiunit 900 MW class CANDU® reactors, the calandria vessel is suspended within a larger shield tank. Due to temperature changes or changes in moderator fluid levels in the calandria, the calandria can move relative to the shield tank and its reactivity deck. Thimbles which contain the reactivity sensors and controls connect the two vessels and allow the reactivity drives and controls connections to be placed on the deck structure on the top of the reactor assembly for RRS and SDS1 and horizontally for SDS2. These thimbles have expansion joints with metal bellows where they meet the deck structure or shield tank walls. The deck structure lies on a vault containment boundary. The horizontal ion chambers are not in the containment boundary as they connect the outside of the calandria and shield tank around mid plane in the reactor vault, but due to geometry difference provides a more challenging work environment. Bruce had a beetle alarm (1-63851-MIA2-ME30 in alarm state (vertical IC housing)) at the start of April 2012 on Unit 1 channel F vertical Ion chamber expansion joint at the deck connection. This occurred after the moderator levels had been raised after the several years long refurbishment outage and the expansion joint had a significant travel. The investigation showed shield tank water in the collection chamber at the beetle. In addition, Channel J of the horizontal ion chamber had a seized instrument, which on removal was found to relate to oxide build up as a result of minor water leakage into the site. Repairs in both cases were performed as part of the long Bruce 1 & 2 refurbishment outage to completely stop the

  7. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors.

    Science.gov (United States)

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-06-10

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L).

  8. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors

    Directory of Open Access Journals (Sweden)

    Ivan Felis

    2016-06-01

    Full Text Available Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L.

  9. Falling liquid film flow along cascade-typed first wall of laser-fusion reactor

    International Nuclear Information System (INIS)

    Kunugi, T.; Nakai, T.; Kawara, Z.

    2007-01-01

    To protect from high energy/particle fluxes caused by nuclear fusion reaction such as extremely high heat flux, X rays, Alpha particles and fuel debris to a first wall of an inertia fusion reactor, a 'cascade-typed' first wall with a falling liquid film flow is proposed as the 'liquid wall' concept which is one of the reactor chamber cooling and wall protection schemes: the reactor chamber can protect by using a liquid metal film flow (such as Li 17 Pb 83 ) over the wall. In order to investigate the feasibility of this concept, we conducted the numerical analyses by using the STREAM code and also conducted the flow visualization experiments. The numerical results suggested that the cascade structure design should be improved, so that we redesigned the cascade-typed first wall and performed the flow visualization as a POP (proof-of-principle) experiment. In the numerical analyses, the water is used as the working liquid and an acrylic plate as the wall. These selections are based on two reasons: (1) from the non-dimensional analysis approach, the Weber number (We=ρu 2 δ/σ: ρ is density, u is velocity, δ is film thickness, σ is surface tension coefficient) should be the same between the design (Li 17 Pb 83 flow) and the model experiment (water flow) because of the free-surface instability, (2) the SiC/SiC composite would be used as the wall material, so that the wall may have the less wettability: the acrylic plate has the similar feature. The redesigned cascade-typed first wall for one step (30 cm height corresponding to 4 Hz laser duration) consists of a liquid tank having a free-surface for keeping the constant water-head located at the backside of the first wall, and connects to a slit which is composed of two plates: one plate is the first wall, and the other is maintaining the liquid level. This design solved the trouble of the previous design. The test section for the flow visualization has the same structure and the same height as the reactor design

  10. The central drift chamber for the D0 experiment: Design, construction and test

    International Nuclear Information System (INIS)

    Behnke, T.

    1989-08-01

    A cylindrical drift chamber has been designed and built at the State University of New York at Stony Brook. This chamber is to be installed in the D0 detector which is being completed at the Fermi National Accelerator. In this dissertation the design, construction and testing of this chamber are described. The characteristic features of this chamber are cells formed by solid walls and a modular structure. Much discussion is given to the performance of and results from a chamber made from three final modules which was installed in the D0 interaction region during the 1988/1989 collider run. Using this chamber proton anti-proton interactions were measured at the D0 interaction point

  11. The central drift chamber for the D0 experiment: Design, construction and test

    Energy Technology Data Exchange (ETDEWEB)

    Behnke, Ties [State Univ. of New York (SUNY), Stony Brook, NY (United States)

    1989-08-01

    A cylindrical drift chamber has been designed and built at the State University of New York at Stony Brook. This chamber is to be installed in the D0 detector which is being completed at the Fermi National Accelerator. In this dissertation the design, construction and testing of this chamber are described. The characteristic features of this chamber are cells formed by solid walls and a modular structure. Much discussion is given to the performance of and results from a chamber made from three final modules which was installed in the D0 interaction region during the 1988/1989 collider run. Using this chamber proton anti-proton interactions were measured at the D0 interaction point.

  12. Mega-bicone vacuum chamber for ISR intersections

    CERN Document Server

    CERN PhotoLab

    1975-01-01

    The cylindrical central part covered the collision region allowing secondary particles emitted at large angle to escape thanks to its very thin wall.The two conical parts are terminated by "transparent" thin windows for letting out forward emitted secondary particles. Vacuum chambers of this shape were made in their thin parts out of 0.3 mm stainless steel or 0.28 mm titanium alloy sheet. See also 7609219, 7609221, 7507132X.

  13. Surgical management of anterior chamber epithelial cysts.

    Science.gov (United States)

    Haller, Julia A; Stark, Walter J; Azab, Amr; Thomsen, Robert W; Gottsch, John D

    2003-03-01

    To review management strategies for treatment of anterior chamber epithelial cysts. Retrospective review of consecutive interventional case series. Charts of patients treated for epithelial ingrowth over a 10-year period by a single surgeon were reviewed. Cases of anterior chamber epithelial cysts were identified and recorded, including details of ocular history, preoperative and postoperative acuity, intraocular pressure (IOP), and ocular examination, type of surgical intervention, and details of further procedures performed. Seven eyes with epithelial cysts were identified. Patient age ranged from 1.5 to 53 years at presentation. Four patients were children. In four eyes, cysts were secondary to trauma, one case was presumably congenital, one case developed after corneal perforation in an eye with Terrien's marginal degeneration, and one case developed after penetrating keratoplasty (PK). Three eyes were treated with vitrectomy, en bloc resection of the cyst and associated tissue, fluid-air exchange and cryotherapy. The last four eyes were treated with a new conservative strategy of cyst aspiration (three cases) or local excision (one keratin "pearl" cyst), and endolaser photocoagulation of the collapsed cyst wall/base. All epithelial tissue was successfully eradicated by clinical criteria; one case required repeat excision (follow-up, 9 to 78 months, mean 45). Two eyes required later surgery for elevated IOP, two for cataract extraction and one for repeat PK. Final visual acuity ranged from 20/20 to hand motions, depending on associated ocular damage. Best-corrected visual results were obtained in the more conservatively managed eyes. Anterior chamber epithelial cysts can be managed conservatively in selected cases with good results. This strategy may be particularly useful in children's eyes, where preservation of the lens, iris, and other structures may facilitate amblyopia management. Copyright 2003 by Elsevier Science Inc.

  14. An overview of the development of the first wall and other principal components of a laser fusion power plant

    International Nuclear Information System (INIS)

    Sethian, John D.; Raffray, A. Rene; Latkowski, Jeffery; Blanchard, James P.; Snead, Lance; Renk, Timothy J.; Sharafat, Shahram

    2005-01-01

    This paper introduces the JNM Special Issue on the development of a first wall for the reaction chamber in a laser fusion power plant. In this approach to fusion energy a spherical target is injected into a large chamber and heated to fusion burn by an array of lasers. The target emissions are absorbed by the wall and encapsulating blanket, and the resulting heat converted into electricity. The bulk of the energy deposited in the first wall is in the form of X-rays (1.0-100 keV) and ions (0.1-4 MeV). In order to have a practical power plant, the first wall must be resistant to these emissions and suffer virtually no erosion on each shot. A wall candidate based on tungsten armor bonded to a low activation ferritic steel substrate has been chosen as the initial system to be studied. The choice was based on the vast experience with these materials in a nuclear environment and the ability to address most of the key remaining issues with existing facilities. This overview paper is divided into three parts. The first part summarizes the current state of the development of laser fusion energy. The second part introduces the tungsten armored ferritic steel concept, the three critical development issues (thermo-mechanical fatigue, helium retention, and bonding) and the research to address them. Based on progress to date the latter two appear to be resolvable, but the former remains a challenge. Complete details are presented in the companion papers in this JNM Special Issue. The third part discusses other factors that must be considered in the design of the first wall, including compatibility with blanket concepts, radiological concerns, and structural considerations

  15. An overview of the development of the first wall and other principal components of a laser fusion power plant

    Science.gov (United States)

    Sethian, John D.; Raffray, A. Rene; Latkowski, Jeffery; Blanchard, James P.; Snead, Lance; Renk, Timothy J.; Sharafat, Shahram

    2005-12-01

    This paper introduces the JNM Special Issue on the development of a first wall for the reaction chamber in a laser fusion power plant. In this approach to fusion energy a spherical target is injected into a large chamber and heated to fusion burn by an array of lasers. The target emissions are absorbed by the wall and encapsulating blanket, and the resulting heat converted into electricity. The bulk of the energy deposited in the first wall is in the form of X-rays (1.0-100 keV) and ions (0.1-4 MeV). In order to have a practical power plant, the first wall must be resistant to these emissions and suffer virtually no erosion on each shot. A wall candidate based on tungsten armor bonded to a low activation ferritic steel substrate has been chosen as the initial system to be studied. The choice was based on the vast experience with these materials in a nuclear environment and the ability to address most of the key remaining issues with existing facilities. This overview paper is divided into three parts. The first part summarizes the current state of the development of laser fusion energy. The second part introduces the tungsten armored ferritic steel concept, the three critical development issues (thermo-mechanical fatigue, helium retention, and bonding) and the research to address them. Based on progress to date the latter two appear to be resolvable, but the former remains a challenge. Complete details are presented in the companion papers in this JNM Special Issue. The third part discusses other factors that must be considered in the design of the first wall, including compatibility with blanket concepts, radiological concerns, and structural considerations.

  16. An overview of the development of the first wall and other principal components of a laser fusion power plant

    Energy Technology Data Exchange (ETDEWEB)

    Sethian, John D. [Plasma Physics Division, Naval Research Laboratory, 4555 Overlook Av. SW, Washington, DC 20375 (United States)]. E-mail: sethian@this.nrl.navy.mil; Raffray, A. Rene [University of California, San Diego, La Jolla, CA 92093 (United States); Latkowski, Jeffery [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Blanchard, James P. [University of Wisconsin, Madison, WI 53706 (United States); Snead, Lance [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Renk, Timothy J. [Sandia National Laboratory, Albuquerque, NM 87185 (United States); Sharafat, Shahram [University of California, Los Angeles, Los Angeles, CA 90095 (United States)

    2005-12-15

    This paper introduces the JNM Special Issue on the development of a first wall for the reaction chamber in a laser fusion power plant. In this approach to fusion energy a spherical target is injected into a large chamber and heated to fusion burn by an array of lasers. The target emissions are absorbed by the wall and encapsulating blanket, and the resulting heat converted into electricity. The bulk of the energy deposited in the first wall is in the form of X-rays (1.0-100 keV) and ions (0.1-4 MeV). In order to have a practical power plant, the first wall must be resistant to these emissions and suffer virtually no erosion on each shot. A wall candidate based on tungsten armor bonded to a low activation ferritic steel substrate has been chosen as the initial system to be studied. The choice was based on the vast experience with these materials in a nuclear environment and the ability to address most of the key remaining issues with existing facilities. This overview paper is divided into three parts. The first part summarizes the current state of the development of laser fusion energy. The second part introduces the tungsten armored ferritic steel concept, the three critical development issues (thermo-mechanical fatigue, helium retention, and bonding) and the research to address them. Based on progress to date the latter two appear to be resolvable, but the former remains a challenge. Complete details are presented in the companion papers in this JNM Special Issue. The third part discusses other factors that must be considered in the design of the first wall, including compatibility with blanket concepts, radiological concerns, and structural considerations.

  17. Comparing calibration methods of electron beams using plane-parallel chambers with absorbed-dose to water based protocols

    International Nuclear Information System (INIS)

    Stewart, K.J.; Seuntjens, J.P.

    2002-01-01

    Recent absorbed-dose-based protocols allow for two methods of calibrating electron beams using plane-parallel chambers, one using the N D,w Co for a plane-parallel chamber, and the other relying on cross-calibration of the plane-parallel chamber in a high-energy electron beam against a cylindrical chamber which has an N D,w Co factor. The second method is recommended as it avoids problems associated with the P wall correction factors at 60 Co for plane-parallel chambers which are used in the determination of the beam quality conversion factors. In this article we investigate the consistency of these two methods for the PTW Roos, Scanditronics NACP02, and PTW Markus chambers. We processed our data using both the AAPM TG-51 and the IAEA TRS-398 protocols. Wall correction factors in 60 Co beams and absorbed-dose beam quality conversion factors for 20 MeV electrons were derived for these chambers by cross-calibration against a cylindrical ionization chamber. Systematic differences of up to 1.6% were found between our values of P wall and those from the Monte Carlo calculations underlying AAPM TG-51, and up to 0.6% when comparing with the IAEA TRS-398 protocol. The differences in P wall translate directly into differences in the beam quality conversion factors in the respective protocols. The relatively large spread in the experimental data of P wall , and consequently the absorbed-dose beam quality conversion factor, confirms the importance of the cross-calibration technique when using plane-parallel chambers for calibrating clinical electron beams. We confirmed that for well-guarded plane-parallel chambers, the fluence perturbation correction factor at d max is not significantly different from the value at d ref . For the PTW Markus chamber the variation in the latter factor is consistent with published fits relating it to average energy at depth

  18. Micro plate fission chamber development

    International Nuclear Information System (INIS)

    Wang Mei; Wen Zhongwei; Lin Jufang; Jiang Li; Liu Rong; Wang Dalun

    2014-01-01

    To conduct the measurement of neutron flux and the fission rate distribution at several position in assemblies, the micro plate fission chamber was designed and fabricated. Since the requirement of smaller volume and less structure material was taken into consideration, it is convinient, commercial and practical to use fission chamber to measure neutron flux in specific condition. In this paper, the structure of fission chamber and process of fabrication were introduced and performance test result was presented. The detection efficiency is 91.7%. (authors)

  19. Proton beam monitor chamber calibration

    International Nuclear Information System (INIS)

    Gomà, C; Meer, D; Safai, S; Lorentini, S

    2014-01-01

    The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences—of the order of 3%—were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth—i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers—rather than cylindrical chambers—for the reference dosimetry of pseudo-monoenergetic proton beams. (paper)

  20. A small flat fission chamber

    International Nuclear Information System (INIS)

    Li Yijun; Wang Dalun; Chen Suhe

    1999-01-01

    With fission materials of depleted uranium, natural uranium, enriched uranium, 239 Pu, and 237 Np, the authors have designed and made a series of small flat fission chamber. The authors narrated the construction of the fission chamber and its technological process of manufacture, and furthermore, the authors have measured and discussed the follow correct factor, self-absorption, boundary effect, threshold loss factor, bottom scatter and or so

  1. Advances on fission chamber modelling

    International Nuclear Information System (INIS)

    Filliatre, Philippe; Jammes, Christian; Geslot, Benoit; Veenhof, Rob

    2013-06-01

    In-vessel, online neutron flux measurements are routinely performed in mock-up and material testing reactors by fission chambers. Those measurements have a wide range of applications, including characterization of experimental conditions, reactor monitoring and safety. Depending on the application, detectors may experience a wide range of constraints, of several magnitudes, in term of neutron flux, gamma-ray flux, temperature. Hence, designing a specific fission chamber and measuring chain for a given application is a demanding task. It can be achieved by a combination of experimental feedback and simulating tools, the latter being based on a comprehensive understanding of the underlying physics. A computation route that simulates fission chambers, named CHESTER, is presented. The retrieved quantities of interest are the neutron-induced charge spectrum, the electronic and ionic pulses, the mean current and variance, the power spectrum. It relies on the GARFIELD suite, originally developed for drift chambers, and makes use of the MAGBOLTZ code to assess the drift parameters of electrons within the filling gas, and the SRIM code to evaluate the stopping range of fission products. The effect of the gamma flux is also estimated. Computations made with several fission chambers exemplify the possibilities of the route. A good qualitative agreement is obtained when comparing the results with the experimental data available to date. In a near future, a comprehensive experimental programme will be undertaken to qualify the route using the known neutron sources, mock-up reactors and wide choice of fission chambers, with a stress on the predictiveness of the Campbelling mode. Depending on the results, a refinement of the modelling and an effort on the accuracy of input data are also to be considered. CHESTER will then make it possible to predict the overall sensitivity of a chamber, and to optimize the design for a given application. Another benefit will be to increase the

  2. BEBC Big European Bubble Chamber

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    A view of the dismantling of the magnet of BEBC, the 3.7 m European Bubble Chamber : iron magnetic shielding ; lower and upper parts of the vacuum enclosure of the magnet; turbo-molecular vacuum pumps for the "fish-eye" windows; the two superconducting coils; a handling platform; the two cryostats suspended from the bar of the travelling crane which has a 170 ton carrying capacity. The chamber proper, not dismantled, is inside the shielding.

  3. The OPAL vertex drift chamber

    International Nuclear Information System (INIS)

    Carter, J.R.; Elcombe, P.A.; Hill, J.C.; Roach, C.M.; Armitage, J.C.; Carnegie, R.K.; Estabrooks, P.; Hemingway, R.; Karlen, D.; McPherson, A.; Pinfold, J.; Roney, J.M.; Routenburg, P.; Waterhouse, J.; Hargrove, C.K.; Klem, D.; Oakham, F.G.; Carter, A.A.; Jones, R.W.L.; Lasota, M.M.B.; Lloyd, S.L.; Pritchard, T.W.; Wyatt, T.R.

    1990-01-01

    A high precision vertex drift chamber has been installed in the OPAL experiment at LEP. The design of the chamber and the associated readout electronics is described. The performance of the system has been studied using cosmic ray muons and the results of these studies are presented. A space resolution of 50 μm in the drift direction is obtained using the OPAL central detector gas mixture at 4 bar. (orig.)

  4. Bluetooth Communication Interface for EEG Signal Recording in Hyperbaric Chambers.

    Science.gov (United States)

    Pastena, Lucio; Formaggio, Emanuela; Faralli, Fabio; Melucci, Massimo; Rossi, Marco; Gagliardi, Riccardo; Ricciardi, Lucio; Storti, Silvia F

    2015-07-01

    Recording biological signals inside a hyperbaric chamber poses technical challenges (the steel walls enclosing it greatly attenuate or completely block the signals as in a Faraday cage), practical (lengthy cables creating eddy currents), and safety (sparks hazard from power supply to the electronic apparatus inside the chamber) which can be overcome with new wireless technologies. In this technical report we present the design and implementation of a Bluetooth system for electroencephalographic (EEG) recording inside a hyperbaric chamber and describe the feasibility of EEG signal transmission outside the chamber. Differently from older systems, this technology allows the online recording of amplified signals, without interference from eddy currents. In an application of this technology, we measured EEG activity in professional divers under three experimental conditions in a hyperbaric chamber to determine how oxygen, assumed at a constant hyperbaric pressure of 2.8 ATA , affects the bioelectrical activity. The EEG spectral power estimated by fast Fourier transform and the cortical sources of the EEG rhythms estimated by low-resolution brain electromagnetic analysis were analyzed in three different EEG acquisitions: breathing air at sea level; breathing oxygen at a simulated depth of 18 msw, and breathing air at sea level after decompression.

  5. PEP quark search proportional chambers

    Energy Technology Data Exchange (ETDEWEB)

    Parker, S I; Harris, F; Karliner, I; Yount, D [Hawaii Univ., Honolulu (USA); Ely, R; Hamilton, R; Pun, T [California Univ., Berkeley (USA). Lawrence Berkeley Lab.; Guryn, W; Miller, D; Fries, R [Northwestern Univ., Evanston, IL (USA)

    1981-04-01

    Proportional chambers are used in the PEP Free Quark Search to identify and remove possible background sources such as particles traversing the edges of counters, to permit geometric corrections to the dE/dx and TOF information from the scintillator and Cerenkov counters, and to look for possible high cross section quarks. The present beam pipe has a thickness of 0.007 interaction lengths (lambdasub(i)) and is followed in both arms each with 45/sup 0/ <= theta <= 135/sup 0/, ..delta..phi=90/sup 0/ by 5 proportional chambers, each 0.0008 lambdasub(i) thick with 32 channels of pulse height readout, and by 3 thin scintillator planes, each 0.003 lambdasub(i) thick. Following this thin front end, each arm of the detector has 8 layers of scintillator (one with scintillating light pipes) interspersed with 4 proportional chambers and a layer of lucite Cerenkov counters. Both the calculated ion statistics and measurements using He-CH/sub 4/ gas in a test chamber indicate that the chamber efficiencies should be >98% for q=1/3. The Landau spread measured in the test was equal to that observed for normal q=1 traversals. One scintillator plane and thin chamber in each arm will have an extra set of ADC's with a wide gate bracketing the normal one so timing errors and tails of earlier pulses should not produce fake quarks.

  6. Determination of the Kwall correction factor for a cylindrical ionization chamber to measure air-kerma in 60Co gamma beams

    International Nuclear Information System (INIS)

    Laitano, R.F.; Toni, M.P.; Pimpinella, M.; Bovi, M.

    2002-01-01

    The factor K wall to correct for photon attenuation and scatter in the wall of ionization chambers for 60 Co air-kerma measurement has been traditionally determined by a procedure based on a linear extrapolation of the chamber current to zero wall thickness. Monte Carlo calculations by Rogers and Bielajew (1990 Phys. Med. Biol. 35 1065-78) provided evidence, mostly for chambers of cylindrical and spherical geometry, of appreciable deviations between the calculated values of K wall and those obtained by the traditional extrapolation procedure. In the present work an experimental method other than the traditional extrapolation procedure was used to determine the K wall factor. In this method the dependence of the ionization current in a cylindrical chamber was analysed as a function of an effective wall thickness in place of the physical (radial) wall thickness traditionally considered in this type of measurement. To this end the chamber wall was ideally divided into distinct regions and for each region an effective thickness to which the chamber current correlates was determined. A Monte Carlo calculation of attenuation and scatter effects in the different regions of the chamber wall was also made to compare calculation to measurement results. The K wall values experimentally determined in this work agree within 0.2% with the Monte Carlo calculation. The agreement between these independent methods and the appreciable deviation (up to about 1%) between the results of both these methods and those obtained by the traditional extrapolation procedure support the conclusion that the two independent methods providing comparable results are correct and the traditional extrapolation procedure is likely to be wrong. The numerical results of the present study refer to a cylindrical cavity chamber like that adopted as the Italian national air-kerma standard at INMRI-ENEA (Italy). The method used in this study applies, however, to any other chamber of the same type. (author)

  7. Conceptual design strategy for liquid-metal-wall inertial-fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Monsler, M.J.; Meier, W.R.

    1981-02-01

    The liquid-metal-wall chamber has emerged as an attractive reactor concept for inertial fusion energy conversion. The principal feature of this concept is a thick, free-flowing blanket of liquid metal used to protect the structure of the reactor. The development and design of liquid-metal-wall chambers over the past decade provides a basis for formulating a conceptual design strategy for such chambers. Both the attractive and unattractive features of a LMW chamber are enumerated, and a design strategy is formulated which accommodates the engineering constraints while minimizing the liquid-metal flow rate.

  8. Conceptual design strategy for liquid-metal-wall inertial-fusion reactors

    International Nuclear Information System (INIS)

    Monsler, M.J.; Meier, W.R.

    1981-02-01

    The liquid-metal-wall chamber has emerged as an attractive reactor concept for inertial fusion energy conversion. The principal feature of this concept is a thick, free-flowing blanket of liquid metal used to protect the structure of the reactor. The development and design of liquid-metal-wall chambers over the past decade provides a basis for formulating a conceptual design strategy for such chambers. Both the attractive and unattractive features of a LMW chamber are enumerated, and a design strategy is formulated which accommodates the engineering constraints while minimizing the liquid-metal flow rate

  9. Electret ionization chamber: a new method for detection and dosimetry of thermal neutrons

    International Nuclear Information System (INIS)

    Ghilardi, A.J.P.

    1988-01-01

    An electret ionization chamber with boron coated walls is presented as a new method for detecting thermal neutrons. The efficiency of electret ionization chambers with different wall materials for the external electrode was inferred from the results. Detection of slow neutrons with discrimination against the detection of γ-rays and energetic neutrons was shown to depend on the selection of these materials. The charge stability over a long period of time and the charge decay owing to natural radiation were also studied. Numerical analysis was developed by the use of a micro-computer PC-XT. Both the experimental and numerical results show that the sensitivity of the electret ionization chamber for detection of thermal neutrons is comparable with that of the BF 3 ionization chamber and that new technologies for deposition of the boron layer will produce higher efficiency detectors. (author). 102 refs, 32 fig, 10 tabs

  10. Modeling of gas-phase chemistry in the chemical vapor deposition of polysilicon in a cold wall system

    Energy Technology Data Exchange (ETDEWEB)

    Toprac, A.J.; Edgar, T.F.; Trachtenberg, I. (Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering)

    1993-06-01

    The relative contribution of gas-phase chemistry to deposition processes is an important issue both from the standpoint of operation and modeling of these processes. In polysilicon deposition from thermally activated silane in a cold wall rapid thermal chemical vapor deposition (RTCVD) system, the relative contribution of gas-phase chemistry to the overall deposition rate was examined by a mass-balance model. Evaluating the process at conditions examined experimentally, the model indicated that gas-phase reactions may be neglected to good accuracy in predicting polysilicon deposition rate. The model also provided estimates of the level of gas-phase generated SiH[sub 2] associated with deposition on the cold-process chamber walls.

  11. First wall

    International Nuclear Information System (INIS)

    Omori, Junji.

    1991-01-01

    Graphite and C/C composite are used recently for the first wall of a thermonuclear device since materials with small atom number have great impurity allowable capacity for plasmas. Among them, those materials having high thermal conduction are generally anisotropic and have an upper limit for the thickness upon production. Then, anisotropic materials are used for a heat receiving plate, such that the surfaces of the heat receiving plate on the side of lower heat conductivity are brought into contact with each other, and the side of higher thermal conductivity is arranged in parallel with small radius direction and the toroidal direction of the thermonuclear device. As a result, the incident heat on an edge portion can be transferred rapidly to the heat receiving plate, which can suppress the temperature elevation at the surface to thereby reduce the amount of abrasion. Since the heat expansion coefficient of the anisotropic materials is great in the direction of the lower heat conductivity and small in the direction of the higher heat conductivity, the gradient of a thermal load distribution in the direction of the higher heat expansion coefficient is small, and occurrence of thermal stresses due to temperature difference is reduced, to improve the reliability. (N.H.)

  12. Falling walls

    CERN Multimedia

    It was 20 years ago this week that the Berlin wall was opened for the first time since its construction began in 1961. Although the signs of a thaw had been in the air for some time, few predicted the speed of the change that would ensue. As members of the scientific community, we can take a moment to reflect on the role our field played in bringing East and West together. CERN’s collaboration with the East, primarily through links with the Joint Institute for Nuclear Research, JINR, in Dubna, Russia, is well documented. Less well known, however, is the role CERN played in bringing the scientists of East and West Germany together. As the Iron curtain was going up, particle physicists on both sides were already creating the conditions that would allow it to be torn down. Cold war historian Thomas Stange tells the story in his 2002 CERN Courier article. It was my privilege to be in Berlin on Monday, the anniversary of the wall’s opening, to take part in a conference entitled &lsquo...

  13. Investigating the contamination of accelerated radioactive beams with an ionization chamber at MINIBALL

    CERN Document Server

    Zidarova, Radostina

    2017-01-01

    My summer student project involved the operation and calibration of an ionization chamber, which was used at MINIBALL for investigating and determining the contamination in post-accelerated radioactive beams used for Coulomb excitation and transfer reaction experiments.

  14. Improved Rhenium Thrust Chambers for In-Space Propulsion, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation-cooled, bipropellant thrust chambers are being considered for the ascent/descent engines and reaction control systems for NASA missions such as Mars Sample...

  15. Thin liquid films with time-dependent chemical reactions sheared by an ambient gas flow

    Science.gov (United States)

    Bender, Achim; Stephan, Peter; Gambaryan-Roisman, Tatiana

    2017-08-01

    Chemical reactions in thin liquid films are found in many industrial applications, e.g., in combustion chambers of internal combustion engines where a fuel film can develop on pistons or cylinder walls. The reactions within the film and the turbulent outer gas flow influence film stability and lead to film breakup, which in turn can lead to deposit formation. In this work we examine the evolution and stability of a thin liquid film in the presence of a first-order chemical reaction and under the influence of a turbulent gas flow. Long-wave theory with a double perturbation analysis is used to reduce the complexity of the problem and obtain an evolution equation for the film thickness. The chemical reaction is assumed to be slow compared to film evolution and the amount of reactant in the film is limited, which means that the reaction rate decreases with time as the reactant is consumed. A linear stability analysis is performed to identify the influence of reaction parameters, material properties, and environmental conditions on the film stability limits. Results indicate that exothermic reactions have a stabilizing effect whereas endothermic reactions destabilize the film and can lead to rupture. It is shown that an initially unstable film can become stable with time as the reaction rate decreases. The shearing of the film by the external gas flow leads to the appearance of traveling waves. The shear stress magnitude has a nonmonotonic influence on film stability.

  16. Diagnostic techniques for measuring temperature transients and stress transients in the first wall of an ICF reactor

    International Nuclear Information System (INIS)

    Melamed, N.T.; Taylor, L.H.

    1983-01-01

    The primary challenge in the design of an Inertial Confinement Fusion (ICF) power reactor is to make the first wall survive the frequent explosions of the pellets. Westinghouse has proposed a dry wall design consisting of steel tubes coated with tantalum. This report describes the design of a test chamber and two diagnostic procedures for experimentally determining the reliability of the Westinghouse design. The test chamber simulates the x-ray and ion pulse irradiation of the wall due to a pellet explosion. The diagnostics consist of remote temperature sensing and surface deformation measurements. The chamber and diagnostics can also be used to test other first-wall designs

  17. Mechanisms of differentiation in the Skaergaard magma chamber

    Science.gov (United States)

    Tegner, C.; Lesher, C. E.; Holness, M. B.; Jakobsen, J. K.; Salmonsen, L. P.; Humphreys, M. C. S.; Thy, P.

    2012-04-01

    The Skaergaard intrusion is a superb natural laboratory for studying mechanisms of magma chamber differentiation. The magnificent exposures and new systematic sample sets of rocks that solidified inwards from the roof, walls and floor of the chamber provide means to test the relative roles of crystal settling, diffusion, convection, liquid immiscibility and compaction in different regions of the chamber and in opposite positions relative to gravity. Examination of the melt inclusions and interstitial pockets has demonstrated that a large portion of intrusion crystallized from an emulsified magma chamber composed of immiscible silica- and iron-rich melts. The similarity of ratios of elements with opposite partitioning between the immiscible melts (e.g. P and Rb) in wall, floor and roof rocks, however, indicate that large-scale separation did not occur. Yet, on a smaller scale of metres to hundred of metres and close to the interface between the roof and floor rocks (the Sandwich Horizon), irregular layers and pods of granophyre hosted by extremely iron-rich cumulates point to some separation of the two liquid phases. Similar proportions of the primocryst (cumulus) minerals in roof, wall and floor rocks indicate that crystal settling was not an important mechanism. Likewise, the lack of fractionation of elements with different behavior indicate that diffusion and fluid-driven metasomatism played relatively minor roles. Compositional convection and/or compaction within the solidifying crystal mush boundary layer are likely the most important mechanisms. A correlation of low trapped liquid fractions (calculated from strongly incompatible elements) in floor rocks with high fractionation density (the density difference between the crystal framework and the liquid) indicate that compaction is the dominating process in expelling evolved liquid from the crystal mush layer. This is supported by high and variable trapped liquid contents in the roof rocks, where gravity

  18. Directional muon jet chamber for a muon collider (Groovy Chamber)

    International Nuclear Information System (INIS)

    Atac, M.

    1996-10-01

    A directional jet drift chamber with PAD readout is proposed here which can select vertex originated muons within a given time window and eliminate those muons which primarily originate upstream, using only a PAD readout. Drift time provides the Z-coordinate, and the center of gravity of charge distribution provides the r-ψ coordinates. Directionality at the trigger level is obtained by the timing measurement from the PAD hits within a given time window. Because of the long drift time between the bunch crossings, a muon collider enables one to choose a drift distance in the drift chamber as long as 50 cm. This is an important factor in reducing cost of drift chambers which have to cover relatively large areas

  19. Investigation on the electron flux to the wall in the VENUS ion source

    Energy Technology Data Exchange (ETDEWEB)

    Thuillier, T., E-mail: thuillier@lpsc.in2p3.fr; Angot, J. [LPSC, Université Grenoble-Alpes, CNRS/IN2P3, 53 rue des Martyrs, 38026 Grenoble Cedex (France); Benitez, J. Y.; Hodgkinson, A.; Lyneis, C. M.; Todd, D. S.; Xie, D. Z. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2016-02-15

    The long-term operation of high charge state electron cyclotron resonance ion sources fed with high microwave power has caused damage to the plasma chamber wall in several laboratories. Porosity, or a small hole, can be progressively created in the chamber wall which can destroy the plasma chamber over a few year time scale. A burnout of the VENUS plasma chamber is investigated in which the hole formation in relation to the local hot electron power density is studied. First, the results of a simple model assuming that hot electrons are fully magnetized and strictly following magnetic field lines are presented. The model qualitatively reproduces the experimental traces left by the plasma on the wall. However, it is too crude to reproduce the localized electron power density for creating a hole in the chamber wall. Second, the results of a Monte Carlo simulation, following a population of scattering hot electrons, indicate a localized high power deposited to the chamber wall consistent with the hole formation process. Finally, a hypervapotron cooling scheme is proposed to mitigate the hole formation in electron cyclotron resonance plasma chamber wall.

  20. Sympathetic stimulation alters left ventricular relaxation and chamber size.

    Science.gov (United States)

    Burwash, I G; Morgan, D E; Koilpillai, C J; Blackmore, G L; Johnstone, D E; Armour, J A

    1993-01-01

    Alterations in left ventricular (LV) contractility, relaxation, and chamber dimensions induced by efferent sympathetic nerve stimulation were investigated in nine anesthetized open-chest dogs in sinus rhythm. Supramaximal stimulation of acutely decentralized left stellate ganglia augmented heart rate, LV systolic pressure, and rate of LV pressure rise (maximum +dP/dt, 1,809 +/- 191 to 6,304 +/- 725 mmHg/s) and fall (maximum -dP/dt, -2,392 +/- 230 to -4,458 +/- 482 mmHg/s). It also reduced the time constant of isovolumic relaxation, tau (36.5 +/- 4.8 to 14.9 +/- 1.1 ms). Simultaneous two-dimensional echocardiography recorded reductions in end-diastolic and end-systolic LV cross-sectional chamber areas (23 and 31%, respectively), an increase in area ejection fraction (32%), and increases in end-diastolic and end-systolic wall thicknesses (14 and 13%, respectively). End-systolic and end-diastolic wall stresses were unchanged by stellate ganglion stimulation (98 +/- 12 to 95 +/- 9 dyn x 10(3)/cm2; 6.4 +/- 2.4 to 2.4 +/- 0.3 dyn x 10(3)/cm2, respectively). Atrial pacing to similar heart rates did not alter monitored indexes of contractility. Dobutamine and isoproterenol induced changes similar to those resulting from sympathetic neuronal stimulation. These data indicate that when the efferent sympathetic nervous system increases left ventricular contractility and relaxation, concomitant reductions in systolic and diastolic dimensions of that chamber occur that are associated with increasing wall thickness such that LV wall stress changes are minimized.

  1. Conceptual design study of the hylife lithium fall laser fusion chamber. FY 1979 annual report

    International Nuclear Information System (INIS)

    1979-01-01

    In FY 1979, the basic configuration of FY 1978 was used as a reference point. Many studies were then made to either generate more design information concerning this design or to produce new concepts that would lead to a superior configuration. Among these activities were a detailed weight analysis, an assembly sequence, a chamber vibration analysis, a splash baffle stress study, and an analysis of first wall thermal stresses. Then some new concepts were introduced that pertained to the first wall, the lithium inlet nozzle, the chamber supports, the inlet piping, and pressure vessel

  2. Dynamic consideration of smog chamber experiments

    Directory of Open Access Journals (Sweden)

    W. K. Chuang

    2017-08-01

    Full Text Available Recent studies of the α-pinene + ozone reaction that address particle nucleation show relatively high molar yields of highly oxidized multifunctional organic molecules with very low saturation concentrations that can form and grow new particles on their own. However, numerous smog-chamber experiments addressing secondary organic aerosol (SOA mass yields, interpreted via equilibrium partitioning theory, suggest that the vast majority of SOA from α-pinene is semivolatile. We explore this paradox by employing a dynamic volatility basis set (VBS model that reproduces the new-particle growth rates observed in the CLOUD experiment at CERN and then modeling SOA mass yield experiments conducted at Carnegie Mellon University (CMU. We find that the base-case simulations do overpredict observed SOA mass but by much less than an equilibrium analysis would suggest; this is because delayed condensation of vapors suppresses the apparent mass yields early in the chamber experiments. We further find that a second VBS model featuring substantial oligomerization of semivolatile monomers can match the CLOUD growth rates with substantially lower SOA mass yields; this is because the lighter monomers have a higher velocity and thus a higher condensation rate for a given mass concentration. The oligomerization simulations are a closer match to the CMU experiments than the base-case simulations, though they overpredict the observations somewhat. However, we also find that if the chemical conditions in CLOUD and the CMU chamber were identical, substantial nucleation would have occurred in the CMU experiments when in fact none occurred. This suggests that the chemical mechanisms differed in the two experiments, perhaps because the high oxidation rates in the SOA formation experiments led to rapid termination of peroxy radical chemistry.

  3. Dynamic consideration of smog chamber experiments

    Science.gov (United States)

    Chuang, Wayne K.; Donahue, Neil M.

    2017-08-01

    Recent studies of the α-pinene + ozone reaction that address particle nucleation show relatively high molar yields of highly oxidized multifunctional organic molecules with very low saturation concentrations that can form and grow new particles on their own. However, numerous smog-chamber experiments addressing secondary organic aerosol (SOA) mass yields, interpreted via equilibrium partitioning theory, suggest that the vast majority of SOA from α-pinene is semivolatile. We explore this paradox by employing a dynamic volatility basis set (VBS) model that reproduces the new-particle growth rates observed in the CLOUD experiment at CERN and then modeling SOA mass yield experiments conducted at Carnegie Mellon University (CMU). We find that the base-case simulations do overpredict observed SOA mass but by much less than an equilibrium analysis would suggest; this is because delayed condensation of vapors suppresses the apparent mass yields early in the chamber experiments. We further find that a second VBS model featuring substantial oligomerization of semivolatile monomers can match the CLOUD growth rates with substantially lower SOA mass yields; this is because the lighter monomers have a higher velocity and thus a higher condensation rate for a given mass concentration. The oligomerization simulations are a closer match to the CMU experiments than the base-case simulations, though they overpredict the observations somewhat. However, we also find that if the chemical conditions in CLOUD and the CMU chamber were identical, substantial nucleation would have occurred in the CMU experiments when in fact none occurred. This suggests that the chemical mechanisms differed in the two experiments, perhaps because the high oxidation rates in the SOA formation experiments led to rapid termination of peroxy radical chemistry.

  4. Spherical ionization chamber of 14 liter for precise measurement of environmental radiation dose rate

    International Nuclear Information System (INIS)

    Nagaoka, Toshi; Saito, Kimiaki; Moriuchi, Shigeru

    1991-05-01

    A spherical ionization chamber of 14 liter filled with 1 atm. nitrogen gas was arranged aiming at precise measurement of dose rate due to environmental gamma rays and cosmic rays. Ionization current-dose rate conversion factor for this ionization chamber was derived from careful consideration taking into account the attenuation by chamber wall, ionization current due to alpha particles and so on. Experiments at calibrated gamma ray fields and intercomparison with NaI(Tl) scintillation detector were also performed, which confirmed this ionization chamber using the conversion factor can measure the dose rate with an error of only a few percent. This ionization chamber will be used for measurement of environmental gamma ray and cosmic ray dose rate. (author)

  5. Integrated Chamber Design for the Laser Inertial Fusion Energy (LIFE) Engine

    Energy Technology Data Exchange (ETDEWEB)

    Latkowski, J F; Kramer, K J; Abbott, R P; Morris, K R; DeMuth, J; Divol, L; El-Dasher, B; Lafuente, A; Loosmore, G; Reyes, S; Moses, G A; Fratoni, M; Flowers, D; Aceves, S; Rhodes, M; Kane, J; Scott, H; Kramer, R; Pantano, C; Scullard, C; Sawicki, R; Wilks, S; Mehl, M

    2010-12-07

    The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. A key component of a LIFE engine is the fusion chamber subsystem. The present work details the chamber design for the pure fusion option. The fusion chamber consists of the first wall and blanket. This integrated system must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets, and enable both target and laser beam transport to the ignition point. The chamber system also must mitigate target emissions, including ions, x-rays and neutrons and reset itself to enable operation at 10-15 Hz. Finally, the chamber must offer a high level of availability, which implies both a reasonable lifetime and the ability to rapidly replace damaged components. An integrated LIFE design that meets all of these requirements is described herein.

  6. Integrated Chamber Design for the Laser Inertial Fusion Energy (LIFE) Engine

    International Nuclear Information System (INIS)

    Latkowski, J.F.; Kramer, K.J.; Abbott, R.P.; Morris, K.R.; DeMuth, J.; Divol, L.; El-Dasher, B.; Lafuente, A.; Loosmore, G.; Reyes, S.; Moses, G.A.; Fratoni, M.; Flowers, D.; Aceves, S.; Rhodes, M.; Kane, J.; Scott, H.; Kramer, R.; Pantano, C.; Scullard, C.; Sawicki, R.; Wilks, S.; Mehl, M.

    2010-01-01

    The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. A key component of a LIFE engine is the fusion chamber subsystem. The present work details the chamber design for the pure fusion option. The fusion chamber consists of the first wall and blanket. This integrated system must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets, and enable both target and laser beam transport to the ignition point. The chamber system also must mitigate target emissions, including ions, x-rays and neutrons and reset itself to enable operation at 10-15 Hz. Finally, the chamber must offer a high level of availability, which implies both a reasonable lifetime and the ability to rapidly replace damaged components. An integrated LIFE design that meets all of these requirements is described herein.

  7. "Flat-Fish" Vacuum Chamber

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The picture shows a "Flat-Fish" vacuum chamber being prepared in the ISR workshop for testing prior to installation in the Split Field Magnet (SFM) at intersection I4. The two shells of each part were hydroformed from 0.15 mm thick inconel 718 sheet (with end parts in inconel 600 for easier manual welding to the arms) and welded toghether with two strips which were attached by means of thin stainless steel sheets to the Split Field Magnet poles in order to take the vertical component of the atmospheric pressure force. This was the thinnest vacuum chamber ever made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature. In this picture the thin sheets transferring the vertical component of the atmosferic pressure force are attached to a support frame for testing. See also 7712182, 7712179.

  8. An experimental propane bubble chamber

    International Nuclear Information System (INIS)

    Rogozinski, A.

    1957-01-01

    Describes a propane bubble chamber 10 cm in diameter and 5 cm deep. The body of the chamber is in stainless steel, and it has two windows of polished hardened glass. The compression and decompression of the propane are performed either through a piston in direct contact with the liquid, or by the action on the liquid, through a triple-mylar-Perbunan membrane, of a compressed gas. The general and also optimum working conditions of the chamber are described, and a few results are given concerning, in particular, the tests of the breakage-resistance of the windows and the measurements of the thermal expansion of the compressibility isotherm for the propane employed. (author) [fr

  9. Equipment for handling ionization chamber

    International Nuclear Information System (INIS)

    Altmann, J.

    1988-01-01

    The device consists of an ionization channel with an ionization chamber, of a support ring, axial and radial bearings, a sleeve, a screw gear and an electric motor. The ionization chamber is freely placed on the bottom of the ionization channel. The bottom part of the channel deviates from the vertical axis. The support ring propped against the axial bearing in the sleeve is firmly fixed to the top part of the ionization channel. The sleeve is fixed to the reactor lid. Its bottom part is provided with a recess for the radial bearing which is propped against a screw wheel firmly connected to the ionization channel. In measuring neutron flux, the screw wheel is rotated by the motor, thus rotating the whole ionization channel such that the ionization chamber is displaced into the reactor core.(J.B.). 1 fig

  10. General purpose nuclear irradiation chamber

    International Nuclear Information System (INIS)

    Nurul Fadzlin Hasbullah; Nuurul Iffah Che Omar; Nahrul Khair Alang Md Rashid; Jaafar Abdullah

    2013-01-01

    Nuclear technology has found a great need for use in medicine, industry, and research. Smoke detectors in our homes, medical treatments and new varieties of plants by irradiating its seeds are just a few examples of the benefits of nuclear technology. Portable neutron source such as Californium-252, available at Industrial Technology Division (BTI/ PAT), Malaysian Nuclear Agency, has a 2.645 year half-life. However, 252 Cf is known to emit gamma radiation from the source. Thus, this chamber aims to provide a proper gamma shielding for samples to distinguish the use of mixed neutron with gamma-rays or pure neutron radiation. The chamber is compatible to be used with other portable neutron sources such as 241 Am-Be as well as the reactor TRIGA PUSPATI for higher neutron dose. This chamber was designed through a collaborative effort of Kulliyyah Engineering, IIUM with the Industrial Technology Division (BTI) team, Malaysian Nuclear Agency. (Author)

  11. Holography in small bubble chambers

    International Nuclear Information System (INIS)

    Lecoq, P.

    1984-01-01

    This chapter reports on an experiment to determine the total charm cross section at different incident momenta using the small, heavy liquid bubble chamber HOBC. Holography in liquid hydrogen is also tested using the holographic lexan bubble chamber HOLEBC with the aim of preparing a future holographic experiment in hydrogen. The high intensity tests show that more than 100 incident tracks per hologram do not cause a dramatic effect on the picture quality. Hydrogen is more favorable than freon as the bubble growth is much slower in hydrogen. An advantage of holography is to have the maximum resolution in the full volume of the bubble chamber, which allows a gain in sensitivity by a factor of 10 compared to classical optics as 100 tracks per hologram look reasonable. Holograms are not more difficult to analyze than classical optics high-resolution pictures. The results show that holography is a very powerful technique which can be used in very high resolution particle physics experiments

  12. Hydrodynamics of ultra-relativistic bubble walls

    Directory of Open Access Journals (Sweden)

    Leonardo Leitao

    2016-04-01

    Full Text Available In cosmological first-order phase transitions, gravitational waves are generated by the collisions of bubble walls and by the bulk motions caused in the fluid. A sizeable signal may result from fast-moving walls. In this work we study the hydrodynamics associated to the fastest propagation modes, namely, ultra-relativistic detonations and runaway solutions. We compute the energy injected by the phase transition into the fluid and the energy which accumulates in the bubble walls. We provide analytic approximations and fits as functions of the net force acting on the wall, which can be readily evaluated for specific models. We also study the back-reaction of hydrodynamics on the wall motion, and we discuss the extrapolation of the friction force away from the ultra-relativistic limit. We use these results to estimate the gravitational wave signal from detonations and runaway walls.

  13. Hydrodynamics of ultra-relativistic bubble walls

    Energy Technology Data Exchange (ETDEWEB)

    Leitao, Leonardo, E-mail: lleitao@mdp.edu.ar; Mégevand, Ariel, E-mail: megevand@mdp.edu.ar

    2016-04-15

    In cosmological first-order phase transitions, gravitational waves are generated by the collisions of bubble walls and by the bulk motions caused in the fluid. A sizeable signal may result from fast-moving walls. In this work we study the hydrodynamics associated to the fastest propagation modes, namely, ultra-relativistic detonations and runaway solutions. We compute the energy injected by the phase transition into the fluid and the energy which accumulates in the bubble walls. We provide analytic approximations and fits as functions of the net force acting on the wall, which can be readily evaluated for specific models. We also study the back-reaction of hydrodynamics on the wall motion, and we discuss the extrapolation of the friction force away from the ultra-relativistic limit. We use these results to estimate the gravitational wave signal from detonations and runaway walls.

  14. Test chamber for alpha spectrometry

    Science.gov (United States)

    Larsen, Robert P.

    1977-01-01

    Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

  15. Laboratory Course on Drift Chambers

    International Nuclear Information System (INIS)

    Garcia-Ferreira, Ix-B.; Garcia-Herrera, J.; Villasenor, L.

    2006-01-01

    Drift chambers play an important role in particle physics experiments as tracking detectors. We started this laboratory course with a brief review of the theoretical background and then moved on to the the experimental setup which consisted of a single-sided, single-cell drift chamber. We also used a plastic scintillator paddle, standard P-10 gas mixture (90% Ar, 10% CH4) and a collimated 90Sr source. During the laboratory session the students performend measurements of the following quantities: a) drift velocities and their variations as function of the drift field; b) gas gains and c) diffusion of electrons as they drifted in the gas

  16. The knife-edge chamber

    International Nuclear Information System (INIS)

    Barasch, E.F.; Bowcock, T.J.V.; Drew, M.M.; Elliott, S.M.; Lee, B.; McIntyre, P.M.; Pang, Y.; Popovic, M.; Smith, D.D.

    1990-01-01

    In this paper the design for a new technology for particle track detectors is described. Using standard IC fabrication techniques, a pattern of microscopic knife edges and field-shaping electrodes can be fabricated on a silicon substrate. The knife-edge chamber uniquely offers attractive performance for the track chambers required for SSC detectors, for which no present technology is yet satisfactory. Its features include: excellent radiation hardness (10 Mrad), excellent spatial resolution (∼20 μm), short drift time (20 ns), and large pulse height (1 mV)

  17. Ionization chambers for LET determination

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki

    2010-01-01

    resolution and high sensitivity are necessary. For exact dosimetry which is done using ionization chambers (ICs), the recombination taking place in the IC has to be known. Up to now, recombination is corrected phenomenologically and more practical approaches are currently used. Nevertheless, Jaff´e's theory...... of columnar recombination was designed to model the detector efficiency of an ionization chamber. Here, we have shown that despite the approximations and simplification made, the theory is correct for the LETs typically found in clinical radiotherapy employing particles from protons to carbon ions...

  18. The Mark III vertex chamber

    International Nuclear Information System (INIS)

    Adler, J.; Bolton, T.; Bunnell, K.

    1987-07-01

    The design and construction of the new Mark III vertex chamber is described. Initial tests with cosmic rays prove the ability of track reconstruction and yield triplet resolutions below 50 μm at 3 atm using argon/ethane (50:50). Also performed are studies using a prototype of a pressurized wire vertex chamber with 8 mm diameter straw geometry. Spatial resolution of 35mm was obtained using dimethyl ether (DME) at 1 atm and 30 μm using argon/ethane (50/50 mixture) at 4 atm. Preliminary studies indicate the DME to adversely affect such materials as aluminized Mylar and Delrin

  19. Selective and regular localization of accessible Pt nanoparticles inside the walls of an ordered silica: Application as a highly active and well-defined heterogeneous catalyst for propene and styrene hydrogenation reactions

    KAUST Repository

    Boualleg, Malika

    2011-12-01

    We describe here an original methodology related to the "build-the-bottle-around-the-ship" approach yielding a highly ordered silica matrix containing regularly distributed Pt nanoparticles (NPs) located inside the silica walls, Pt@{walls}SiO2. The starting colloidal solution of crystalline Pt nanoparticles was obtained from Pt(dba)2 (dba = dibenzylidene acetone) and 3-chloropropylsilane. The resulting nanoparticles (diameter: 2.0 ± 0.4 nm determined by HRTEM) resulted hydrophilic. The NPs present in the THF colloidal solution were incorporated inside the walls of a highly ordered 2D hexagonal mesoporous silica matrix via sol-gel process using a templating route with tetraethylorthosilicate, TEOS, as the silica source, and block copolymer (EthyleneOxide) 20(PropyleneOxide)70(EthyleneOxide)20 (Pluronic P123) as the structure-directing agent. Low-temperature calcination of the crude material at 593 K led to the final solid Pt@{walls}SiO2. Characterization by IR, HRTEM, BF-STEM and HAADF-STEM, SAXS, WAXS, XRD, XPS, H2 chemisorption, etc. of Pt@{walls}SiO2 confirmed the 2D hexagonal structuration and high mesoporosity (870 m2/g) of the material as well as the presence of stable 2-nm-sized crystalline Pt(0) NPs embedded inside the walls of the silica matrix. The material displayed no tendency to NPs sintering or leaching (Pt loading 0.3 wt.%) during its preparation. Pt@{walls}SiO2 was found to be a stable, selective and highly active hydrogenation catalyst. The catalytic performances in propene hydrogenation were tested under chemical regime conditions in a tubular flow reactor (278 K, propene/H2/He = 20/16/1.09 cm3/min, P tot = 1 bar) and were found superior to those of an homologous solid containing Pt NPs along its pore channels Pt@{pores}SiO2 and to those of a classical industrial catalysts Pt/Al2O3, (TOF = 2.3 s-1 vs. TOF = 0.90 and 0.92 s-1, respectively, calculated per surface platinum atoms). Pt@{walls}SiO2 also catalyzes fast and selective styrene

  20. Selective and regular localization of accessible Pt nanoparticles inside the walls of an ordered silica: Application as a highly active and well-defined heterogeneous catalyst for propene and styrene hydrogenation reactions

    KAUST Repository

    Boualleg, Malika; Norsic, Sé bastien; Baudouin, David; Sayah, Reine; Quadrelli, Elsje Alessandra; Basset, Jean-Marie; Candy, Jean Pierre; Dé lichè re, Pierre; Pelzer, Katrin; Veyre, Laurent; Thieuleux, Chloé

    2011-01-01

    We describe here an original methodology related to the "build-the-bottle-around-the-ship" approach yielding a highly ordered silica matrix containing regularly distributed Pt nanoparticles (NPs) located inside the silica walls, Pt@{walls}SiO2. The starting colloidal solution of crystalline Pt nanoparticles was obtained from Pt(dba)2 (dba = dibenzylidene acetone) and 3-chloropropylsilane. The resulting nanoparticles (diameter: 2.0 ± 0.4 nm determined by HRTEM) resulted hydrophilic. The NPs present in the THF colloidal solution were incorporated inside the walls of a highly ordered 2D hexagonal mesoporous silica matrix via sol-gel process using a templating route with tetraethylorthosilicate, TEOS, as the silica source, and block copolymer (EthyleneOxide) 20(PropyleneOxide)70(EthyleneOxide)20 (Pluronic P123) as the structure-directing agent. Low-temperature calcination of the crude material at 593 K led to the final solid Pt@{walls}SiO2. Characterization by IR, HRTEM, BF-STEM and HAADF-STEM, SAXS, WAXS, XRD, XPS, H2 chemisorption, etc. of Pt@{walls}SiO2 confirmed the 2D hexagonal structuration and high mesoporosity (870 m2/g) of the material as well as the presence of stable 2-nm-sized crystalline Pt(0) NPs embedded inside the walls of the silica matrix. The material displayed no tendency to NPs sintering or leaching (Pt loading 0.3 wt.%) during its preparation. Pt@{walls}SiO2 was found to be a stable, selective and highly active hydrogenation catalyst. The catalytic performances in propene hydrogenation were tested under chemical regime conditions in a tubular flow reactor (278 K, propene/H2/He = 20/16/1.09 cm3/min, P tot = 1 bar) and were found superior to those of an homologous solid containing Pt NPs along its pore channels Pt@{pores}SiO2 and to those of a classical industrial catalysts Pt/Al2O3, (TOF = 2.3 s-1 vs. TOF = 0.90 and 0.92 s-1, respectively, calculated per surface platinum atoms). Pt@{walls}SiO2 also catalyzes fast and selective styrene

  1. Testing an hydrogen streamer chamber

    CERN Multimedia

    1975-01-01

    A 2x10 cm gap streamer chamber, 35x55 cm2 in surface, was built and tested at CERN. Good tracks of cosmic rays were obtained up to atmospheric pressure, see F. Rohrbach et al, CERN-LAL (Orsay) Collaboration, Nucl. Instr. Methods 141 (1977) 229. Michel Cathenoz stand on the center.

  2. Bubble chamber: colour enhanced tracks

    CERN Multimedia

    1998-01-01

    This artistically-enhanced image of real particle tracks was produced in the Big European Bubble Chamber (BEBC). Liquid hydrogen is used to create bubbles along the paths of the particles as a piston expands the medium. A magnetic field is produced in the detector causing the particles to travel in spirals, allowing charge and momentum to be measured.

  3. Tasks related to increase of RA reactor exploitation and experimental potential, 01. Designing the protection chamber in the RA reactor hall for handling the radioactive experimental equipment (I-II) Part II, Vol. II

    International Nuclear Information System (INIS)

    Pavicevic, M.

    1963-07-01

    This second volume of the project for construction of the protection chamber in the RA reactor hall for handling the radioactive devices includes the technical description of the chamber, calculation of the shielding wall thickness, bottom lead plate, horizontal stability of the chamber, cost estimation, and the engineering drawings

  4. Contributions to the methodology of multiwire proportional chambers

    International Nuclear Information System (INIS)

    Petrascu, H.

    1993-01-01

    The Ph.D. thesis presents first the realization, testing, optimization, and use of detection equipment based on position sensitive multiwire proportional chambers (MWPC), high resolution proportional counters, and of ΔE,E ionization chambers. In the second chapter it is presented the realization MWPC, in which the coordinate information is obtained by means of LC-delay lines, containing many original constructive elements. By using a system of three MWPC in coincidence, an experimental testing of the theoretically predicted pion generation in the 235 U fission process, was performed. An upper limit of 10 -11 for this process was found. In the 3-rd chapter there are presented the developments of high resolution proportional counters for X-ray spectrometry. Various penning mixtures of high purity gases were studied. The purity of gases was assured by a technology described in a Romanian patents. These counters are currently use in various applications as a rapid analysis of steel marks and in the mining industry. the 4-th chapter is dedicated to the construction and using of ΔE,E closed, high resolution ionization chambers. With these chambers the multinucleon transfer in the 27 Al( 14 M, X) reaction at 116 MeV bombarding energy was investigated. Also this type of chambers was used for the elaboration of an absolute method for analysis and profiling of impurities in silicon wafers. This method is described in the last part of the chapter. (Author) 117 Figs., 8 Tabs., 55 Refs

  5. Hydrostatic Hyperbaric Chamber Ventilation System

    Science.gov (United States)

    Sarguisingh, Miriam J.

    2012-01-01

    The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy (HBOT) available in the developing world for the treatment of a variety of medical conditions. Specifically, HBOT is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. HBOT is simply too expensive and too dangerous to implement in the developing world using standard equipment. The HHC technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system to provide controlled pressurization and adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware

  6. Compact reaction cell for homogenizing and down-blending highly enriched uranium metal

    Science.gov (United States)

    McLean, W. II; Miller, P.E.; Horton, J.A.

    1995-05-02

    The invention is a specialized reaction cell for converting uranium metal to uranium oxide. In a preferred form, the reaction cell comprises a reaction chamber with increasing diameter along its length (e.g. a cylindrical chamber having a diameter of about 2 inches in a lower portion and having a diameter of from about 4 to about 12 inches in an upper portion). Such dimensions are important to achieve the necessary conversion while at the same time affording criticality control and transportability of the cell and product. The reaction chamber further comprises an upper port and a lower port, the lower port allowing for the entry of reactant gases into the reaction chamber, the upper port allowing for the exit of gases from the reaction chamber. A diffuser plate is attached to the lower port of the reaction chamber and serves to shape the flow of gas into the reaction chamber. The reaction cell further comprises means for introducing gases into the reaction chamber and a heating means capable of heating the contents of the reaction chamber. The present invention also relates to a method for converting uranium metal to uranium oxide in the reaction cell of the present invention. The invention is useful for down-blending highly enriched uranium metal by the simultaneous conversion of highly enriched uranium metal and natural or depleted uranium metal to uranium oxide within the reaction cell. 4 figs.

  7. Compact reaction cell for homogenizing and down-blanding highly enriched uranium metal

    Science.gov (United States)

    McLean, II, William; Miller, Philip E.; Horton, James A.

    1995-01-01

    The invention is a specialized reaction cell for converting uranium metal to uranium oxide. In a preferred form, the reaction cell comprises a reaction chamber with increasing diameter along its length (e.g. a cylindrical chamber having a diameter of about 2 inches in a lower portion and having a diameter of from about 4 to about 12 inches in an upper portion). Such dimensions are important to achieve the necessary conversion while at the same time affording criticality control and transportability of the cell and product. The reaction chamber further comprises an upper port and a lower port, the lower port allowing for the entry of reactant gasses into the reaction chamber, the upper port allowing for the exit of gasses from the reaction chamber. A diffuser plate is attached to the lower port of the reaction chamber and serves to shape the flow of gas into the reaction chamber. The reaction cell further comprises means for introducing gasses into the reaction chamber and a heating means capable of heating the contents of the reaction chamber. The present invention also relates to a method for converting uranium metal to uranium oxide in the reaction cell of the present invention. The invention is useful for down-blending highly enriched uranium metal by the simultaneous conversion of highly enriched uranium metal and natural or depleted uranium metal to uranium oxide within the reaction cell.

  8. Cold vacuum chamber for diagnostics: Instrumentation and first results

    Science.gov (United States)

    Gerstl, S.; Voutta, R.; Casalbuoni, S.; Grau, A. W.; Holubek, T.; de Jauregui, D. Saez; Bartolini, R.; Cox, M. P.; Longhi, E. C.; Rehm, G.; Schouten, J. C.; Walker, R. P.; Sikler, G.; Migliorati, M.; Spataro, B.

    2014-10-01

    For a proper design of the cryogenic layout of superconducting insertion devices it is necessary to take into account the heat load from the beam to the cold beam tube. In order to measure and possibly understand the beam heat load to a cold bore, a cold vacuum chamber for diagnostics (COLDDIAG) has been built. COLDDIAG is designed in a flexible way, to allow its installation in different light sources. In order to study the beam heat load and the influence of the cryosorbed gas layer, the instrumentation comprises temperature sensors, pressure gauges, and mass spectrometers as well as retarding field analyzers with which it is possible to measure the beam heat load, total pressure, and gas content as well as the flux of particles hitting the chamber walls. In this paper we describe the experimental equipment, the installation of COLDDIAG in the Diamond Light Source and selected examples of the measurements performed to show the capabilities of this unique instrument.

  9. A new gaseous detector for tracking: The blade chamber

    International Nuclear Information System (INIS)

    Ambrosi, G.; Battiston, R.; Levi, G.; Barillari, T.; Susinno, G.; Bergsma, F.; Contin, A.; Labbe, J.C.; Laurenti, G.; Mattern, D.; Simonet, G.; Williams, M.C.S.; Zichichi, A.; Boscherini, D.; Bruni, G.; De Pasquale, S.; Giusti, P.; Maccarrone, G.; Nania, R.; O'Shea, V.; Castro, H.; Galvez, J.; Rivera, F.; Schioppa, M.; Sharma, A.

    1990-01-01

    As part of the LAA project at CERN a prototype of a streamer-chamber in which a blade, instead of a wire, is used as the amplification electrode has been built. A big advantage is that the blade can be bent to follow a curve so that a chamber can be built with cells ideally matched to the geometry of the experiment. Moreover, a blade is very rugged, it can withstand severe mechanical shocks and it is also resistant to damage by sparks. The drift time has been measured and a spatial resolution of 250μm has been achieved. Left-right ambiguity can be solved by measuring the charge asymmetry on the walls. The coordinate along the blade is read by external pickup strips. (orig.)

  10. Coating requirements for an ICF dry-wall design

    International Nuclear Information System (INIS)

    Taylor, L.H.; Sucov, E.W.

    1981-01-01

    A new concept for protecting the first wall of an ICF reactor has been developed which relies heavily on a coating to protect the steel tubes which comprise the first wall. This coating must survive the pellet explosion, be ductile, and be compatible with the materials in the ICF pellet. Calculations indicate that tantalum is the best choice for the coating material and that tantalum coated steel tubes can handle fusion thermal powers of 3500 MW in a 10 m radius spherical chamber

  11. Establishment of a radon test chamber

    International Nuclear Information System (INIS)

    Chen Chingjiang; Liu Chichang; Lin Yuming

    1993-01-01

    A walk-in type radon test chamber of 23 m 3 has been built for testing and calibration of radon measurement instruments. The environmental conditions of the test chamber can be varied within a wide range of values. The design objectives specification, monitoring instruments and testing results of this chamber are discussed. This test chamber is available for domestic radon researchers and its accuracy can be traced to the international standard. A routine intercomparison study will be held annually by using this chamber. Other tests like radon progeny and thoron standard may also be performed in this chamber. (1 fig.)

  12. Department of Nuclear Reaction - Overview

    International Nuclear Information System (INIS)

    Budzanowski, A.

    2000-01-01

    . Muon catalysed dd fusion in solid deuterium at the temperature 3K was studied using ddμ, formation cross-sections previously calculated. Construction of the Forward Wall detectors for the CHIC collaboration at the CELSIUS Synchrotron is described. First tests of the Phoswich detectors were performed. A new Bragg ionization chamber for studies of spallation reactions induced by cosmic protons was manufactured in collaboration with the Jagiellonian University and tested using light heavy ion beams from the Tandem accelerator in Catania. Coalescence model analysis was applied to explain spectra of light nuclei emitted in heavy ion induced reactions at 47 AMeV. This work was done in collaboration with Texas A and M University and the Jagiellonian University. We have also joined the Brahms collaboration at RHIC. Measurements of the transverse polarization of positrons emitted from the decay of polarized muons were performed in collaboration with ETH Zurich and Paul Scherrer Institute. The aim was to study time reversal invariance of weak interaction. (author)

  13. Experimental determination of pcav factors for cylindrical ionisation chambers in electron beams

    International Nuclear Information System (INIS)

    Palm, Aa.; Mattsson, O.

    2000-01-01

    The electron beam method recommended for calibrating plane parallel ionisation chambers involves cavity correction factors for cylindrical chambers. The cavity correction factors in the IAEA TRS-381 Code of Practice are based on measurements at R 100 in a PMMA phantom using PMMA cylindrical chambers having different cavity radii. In the present work the recommended data were confirmed for electron beams delivered by modern medical accelerators by using the very same phantom and ionisation chambers that were used in the original work. From another series of measurements, using four specially designed wall-less chambers in a graphite phantom, the linear relation between p cav and the chamber radius that is the basis for the experimental method, was verified. The method was also used to determine the cavity correction factors for a set of Farmer-like graphite chambers placed in water. Compared to the TRS-381 Code of Practice a smaller correction was found for the cavity perturbation for the graphite chambers used in water. (author)

  14. ELM-Induced Plasma Wall Interactions in DIII-D

    International Nuclear Information System (INIS)

    Rudakov, D.L.; Boedo, J.A.; Yu, J.H.; Brooks, N.H.; Fenstermacher, M.E.; Groth, M.; Hollmann, E.M.; Lasnier, C.J.; McLean, A.G.; Moyer, R.A.; Stangeby, P.C.; Tynan, G.R.; Wampler, W.R.; Watkins, J.G.; West, W.P.; Wong, C.C.; Zeng, L.; Bastasz, R.J.; Buchenauer, D.; Whaley, J.

    2008-01-01

    Intense transient fluxes of particles and heat to the main chamber components induced by edge localized modes (ELMs) are of serious concern for ITER. In DIII-D, plasma interaction with the outboard chamber wall is studied using Langmuir probes and optical diagnostics including a fast framing camera. Camera data shows that ELMs feature helical filamentary structures localized at the low field side of the plasma and aligned with the local magnetic field. During the nonlinear phase of an ELM, multiple filaments are ejected from the plasma edge and propagate towards the outboard wall with velocities of 0.5-0.7 km/s. When reaching the wall, filaments result in 'hot spots'--regions of local intense plasma-material interaction (PMI) where the peak incident particle and heat fluxes are up to 2 orders of magnitude higher than those between ELMs. This interaction pattern has a complicated geometry and is neither toroidally nor poloidally symmetric. In low density/collisionality H-mode discharges, PMI at the outboard wall is almost entirely due to ELMs. In high density/collisionality discharges, contributions of ELMs and inter-ELM periods to PMI at the wall are comparable. A Midplane Material Evaluation Station (MiMES) has been recently installed in order to conduct in situ measurements of erosion/redeposition at the outboard chamber wall, including those caused by ELMs

  15. Investigation of cascade-typed falling liquid film flow along first wall of laser-fusion reactor

    International Nuclear Information System (INIS)

    Kunugi, Tomoaki; Nakai, Tadakatsu; Kawara, Zensaku

    2007-01-01

    To protect from high energy/particle fluxes caused by nuclear fusion reaction such as extremely high heat flux, X rays, Alpha particles and fuel debris to a first wall of an inertia fusion reactor, a ''cascade-typed'' falling liquid film flow is proposed as the ''liquid wall'' concept which is one of the reactor chamber cooling and wall protection schemes: the reactor chamber can protect by using a liquid metal film flow (such as Li 17 Pb 83 ) over the wall. In order to investigate the feasibility of this concept, we conducted the numerical analyses by using the commercial code (STREAM: unsteady three-dimensional general purpose thermofluid code) and also conducted the flow visualization experiments. The numerical results suggested that the cascade structure design should be improved, so that we redesigned the cascade-typed first wall and performed the flow visualization as a POP (proof-of-principle) experiment. In the numerical analyses, the water is used as the working liquid and an acrylic plate as the wall. These selections are based on two reasons: (1) from the non-dimensional analysis approach, the Weber number (We=ru 2 d/s: r is density, u is velocity, d is film thickness, s is surface tension coefficient) should be the same between the design (Li 17 Pb 83 flow) and the model experiment (water flow) because of the free-surface instability, (2) the SiC/SiC composite would be used as the wall material, so that the wall may have the less wettability: the acrylic plate has the similar feature. The redesigned cascade-typed first wall for one step (30 cm height corresponding to 4 Hz laser duration) consists of a liquid tank having a free-surface for keeping the constant waterhead located at the backside of the first wall, and connects to a slit which is composed of two plates: one plate is the first wall, and the other is maintaining the liquid level. This design solved the trouble of the previous design. The test section for the flow visualization has the same

  16. Firefighter Nozzle Reaction

    DEFF Research Database (Denmark)

    Chin, Selena K.; Sunderland, Peter B.; Jomaas, Grunde

    2017-01-01

    to anchor forces, the hose becomes straight. The nozzle reaction is found to equal the jet momentum flow rate, and it does not change when an elbow connects the hose to the nozzle. A forward force must be exerted by a firefighter or another anchor that matches the forward force that the jet would exert...... on a perpendicular wall. Three reaction expressions are derived, allowing it to be determined in terms of hose diameter, jet diameter, flow rate, and static pressure upstream of the nozzle. The nozzle reaction predictions used by the fire service are 56% to 90% of those obtained here for typical firefighting hand...

  17. Simulation studies on a prototype ionization chamber for measurement of personal dose equivalent, Hp(10)

    International Nuclear Information System (INIS)

    Cardoso, J.; Oliveira, C.; Carvalho, A.F.

    2005-01-01

    Full text: The Metrological Laboratory of lonizing Radiation and Radioactivity (LMRIR) of Nuclear and Technological Institute (ITN) has designed and constructed a prototype ionization chamber for direct measurement of the personal dose equivalent, H p (10), similar to the developed by the Physikalisch-Technische Bundesanstalt (PTB) and now commercialized by PTW. Tests already performed had shown that the behaviour of this chamber is very close to the PTB chamber, namely the energy dependence for the x-ray radiation qualities of the ISO 4037-1 narrow series N-30, N-40, N-60, N-80, N-100 and N-120 and also for gamma radiation of 137 Cs and 60 Co. However, the results obtained also show a high dependence on the energy for some incident radiation angles and a low magnitude of the electrical response of the ionization chamber. In order to try to optimize the performance of the chamber, namely to decrease the energy dependence and to improve the magnitude of the electrical response of the ionization chamber, the LMRIR initiated numerical simulation of this ionization chamber using a Monte-Carlo method for simulation of radiation transport using, in a first step, the MCNPX code. So, simulation studies of some physical parameters are been performed in order to optimize the response of the ionization chamber, namely the diameter of the central electrode of the ionization chamber, the thickness of the front wall of the ionization chamber, among others. Preliminary results show that probably the actual geometry of the ionization chamber is not yet the optimized configuration. The simulation study will carry on in order to find the optimum geometry. (author)

  18. Development of multiwire proportional chambers

    CERN Multimedia

    Charpak, G

    1969-01-01

    It has happened quite often in the history of science that theoreticians, confronted with some major difficulty, have successfully gone back thirty years to look at ideas that had then been thrown overboard. But it is rare that experimentalists go back thirty years to look again at equipment which had become out-dated. This is what Charpak and his colleagues did to emerge with the 'multiwire proportional chamber' which has several new features making it a very useful addition to the armoury of particle detectors. In the 1930s, ion-chambers, Geiger- Muller counters and proportional counters, were vital pieces of equipment in nuclear physics research. Other types of detectors have since largely replaced them but now the proportional counter, in new array, is making a comeback.

  19. LEP vacuum chamber, early prototype

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The structure of LEP, with long bending magnets and little access to the vacuum chamber between them, required distributed pumping. This is an early prototype for the LEP vacuum chamber, made from extruded aluminium. The main opening is for the beam. The small channel to the right is for cooling water, to carry away the heat deposited by the synchroton radiation from the beam. The 4 slots in the channel to the left house the strip-shaped ion-getter pumps (see 7810255). The ion-getter pumps depended on the magnetic field of the bending magnets, too low at injection energy for the pumps to function well. Also, a different design was required outside the bending magnets. This design was therefore abandoned, in favour of a thermal getter pump (see 8301153 and 8305170).

  20. Single wire drift chamber design

    International Nuclear Information System (INIS)

    Krider, J.

    1987-01-01

    This report summarizes the design and prototype tests of single wire drift chambers to be used in Fermilab test beam lines. The goal is to build simple, reliable detectors which require a minimum of electronics. Spatial resolution should match the 300 μm rms resolution of the 1 mm proportional chambers that they will replace. The detectors will be used in beams with particle rates up to 20 KHz. Single track efficiency should be at least 99%. The first application will be in the MT beamline, which has been designed for calibration of CDF detectors. A set of four x-y modules will be used to track and measure the momentum of beam particles

  1. MPS II drift chamber system

    International Nuclear Information System (INIS)

    Platner, E.D.

    1982-01-01

    The MPS II detectors are narrow drift space chambers designed for high position resolution in a magnetic field and in a very high particle flux environment. Central to this implementation was the development of 3 multi-channel custom IC's and one multi-channel hybrid. The system is deadtimeless and requires no corrections on an anode-to-anode basis. Operational experience and relevance to ISABELLE detectors is discussed

  2. 2D edge plasma modeling extended up to the main chamber

    Energy Technology Data Exchange (ETDEWEB)

    Dekeyser, W., E-mail: wouter.dekeyser@mech.kuleuven.be [Department of Mechanical Engineering, Katholieke Universiteit Leuven, Celestijnenlaan 300A, 3001 Leuven (Belgium); Baelmans, M. [Department of Mechanical Engineering, Katholieke Universiteit Leuven, Celestijnenlaan 300A, 3001 Leuven (Belgium); Reiter, D.; Boerner, P.; Kotov, V. [Institut fuer Plasmaphysik, Forschungszentrum Juelich GmbH, EURATOM-Association, Trilateral Euregio Cluster, D-52425 Juelich (Germany)

    2011-08-01

    Far SOL plasma flow, and hence main chamber recycling and plasma surface interaction, are today still only very poorly described by current 2D fluid edge codes, such as B2, UEDGE or EDGE2D, due to a common technical limitation. We have extended the B2 plasma fluid solver in the current ITER version of B2-EIRENE (SOLPS4.3) to allow plasma solutions to be obtained up to the 'real vessel wall', at least on the basis of ad hoc far SOL transport models. We apply here the kinetic Monte Carlo Code EIRENE on such plasma solutions to study effects of this model refinement on main chamber fluxes and sputtering, for an ITER configuration. We show that main chamber sputtering may be significantly modified both due to thermalization of CX neutrals in the far SOL and poloidally highly asymmetric plasma wall contact, as compared to hitherto applied teleportation of particle fluxes across this domain.

  3. True and measured outgassing rates of a vacuum chamber with a reversibly adsorbed phase

    Energy Technology Data Exchange (ETDEWEB)

    Akaishi, K. [National Inst. for Fusion Science, Toki, Gifu (Japan); Nakasuga, M. [Graduate School of Energy Science, Kyoto Univ., Uji, Kyoto (Japan); Funato, Y. [Suzuka National College of Technology, Suzuka, Mie (Japan)

    2000-03-01

    A pump down model for a vacuum chamber with a reversibly adsorbed phase is presented. The outgassing equation which predicts the variation of coverage at the wall surface of a vacuum chamber with time is derived. Then the measured and the true outgassing rates are defined. The theoretical measured outgassing rate shows only a very weak dependence for pumping speed. This prediction is opposite to the experimental result that the measured outgassing rate depends significantly on pumping speed. It is discussed that the experimental measured outgassing rate must be described as the product of the effective pumping speed and the measured pressure in the pumped chamber, in which the measured pressure is equivalent to the equilibrium pressure of the wall surface described by the equilibrium adsorption isotherm as a function of the shifted surface coverage {theta}-{delta}{theta} by a small coverage {delta}{theta} from the coverage of a pumping point {delta}. (author)

  4. True and measured outgassing rates of a vacuum chamber with a reversibly adsorbed phase

    International Nuclear Information System (INIS)

    Akaishi, K.; Nakasuga, M.; Funato, Y.

    2000-03-01

    A pump down model for a vacuum chamber with a reversibly adsorbed phase is presented. The outgassing equation which predicts the variation of coverage at the wall surface of a vacuum chamber with time is derived. Then the measured and the true outgassing rates are defined. The theoretical measured outgassing rate shows only a very weak dependence for pumping speed. This prediction is opposite to the experimental result that the measured outgassing rate depends significantly on pumping speed. It is discussed that the experimental measured outgassing rate must be described as the product of the effective pumping speed and the measured pressure in the pumped chamber, in which the measured pressure is equivalent to the equilibrium pressure of the wall surface described by the equilibrium adsorption isotherm as a function of the shifted surface coverage θ-Δθ by a small coverage Δθ from the coverage of a pumping point Δ. (author)

  5. An extended CFD model to predict the pumping curve in low pressure plasma etch chamber

    Science.gov (United States)

    Zhou, Ning; Wu, Yuanhao; Han, Wenbin; Pan, Shaowu

    2014-12-01

    Continuum based CFD model is extended with slip wall approximation and rarefaction effect on viscosity, in an attempt to predict the pumping flow characteristics in low pressure plasma etch chambers. The flow regime inside the chamber ranges from slip wall (Kn ˜ 0.01), and up to free molecular (Kn = 10). Momentum accommodation coefficient and parameters for Kn-modified viscosity are first calibrated against one set of measured pumping curve. Then the validity of this calibrated CFD models are demonstrated in comparison with additional pumping curves measured in chambers of different geometry configurations. More detailed comparison against DSMC model for flow conductance over slits with contraction and expansion sections is also discussed.

  6. Optimization of electret ionization chambers for dosimetry in mixed neutron-gamma fields

    International Nuclear Information System (INIS)

    Doerschel, B.; Pretzsch, G.

    1984-01-01

    The properties of combination dosemeters consisting of two air-filled electret ionization chambers in mixed neutron-gamma fields have been investigated. The first chamber, polyethylene-walled, is sensitive to neutrons and gamma rays, the second, having walls of teflon, is sensitive to gamma rays only. The properties of the dosemeters are determined by the resulting errors and the measuring range. As both properties depend on the dimensions of the electret ionization chambers they have been taken into account in optimizing the dimensions. The results show that with the use of the dosemeters the effective dose equivalent in mixed neutron-gamma fields can be determined nearly independently of the spectra. The lower detection limit is less than 1 mSv and the maximum uncertainty of dose measurements about 12%. (author)

  7. GBO RF Anechoic Chamber & Antenna Test Range

    Data.gov (United States)

    Federal Laboratory Consortium — A shielded anechoic chamber measuring 15 by 15 by 37 feet is located in the Jansky Laboratory at Green Bank. This chamber has been outfitted as a far-field antenna...

  8. The KEK 1 m hydrogen bubble chamber

    International Nuclear Information System (INIS)

    Doi, Yoshikuni; Araoka, Osamu; Hayashi, Kohei; Hayashi, Yoshio; Hirabayashi, Hiromi.

    1978-03-01

    A medium size hydrogen bubble chamber has been constructed at the National Laboratory for High Energy Physics, KEK. The bubble chamber has been designed to be operated with a maximum rate of three times per half a second in every two second repetition time of the accelerator, by utilizing a hydraulic expansion system. The bubble chamber has a one meter diameter and a visible volume of about 280 l. A three-view stereo camera system is used for taking photographic pictures of the chamber. A 2 MW bubble chamber magnet is constructed. The main part of the bubble chamber vessel is supported by the magnet yoke. The magnet gives a maximum field of 18.4 kG at the centre of the fiducial volume of the chamber. The overall system of the KEK 1 m hydrogen bubble chamber facility is described in some detail. Some operational characteristics of the facility are also reported. (auth.)

  9. CHICSi - a compact ultra-high vacuum compatible detector system for nuclear reaction experiments at storage rings. I. General structure, mechanics and UHV compatibility

    International Nuclear Information System (INIS)

    Westerberg, L.; Avdeichikov, V.; Carlen, L.; Golubev, P.; Jakobsson, B.; Rouki, C.; Siwek, A.; Veldhuizen, E.J. van; Whitlow, H.J.

    2003-01-01

    CELSIUS Heavy-Ion Collision Silicon detector system (CHICSi) is a large solid angle, barrel-shaped detector system, housing up to 600 detector telescopes arranged in rotational symmetry around the beam axis. CHICSi measures charged particles and fragments from nuclear reactions. It operates at internal targets of storage rings. In order to optimize space and momentum-space coverage and minimize the low-energy detection limits, CHICSi is designed for use in ultra-high vacuum (UHV, ∼10 -8 Pa) inside a cluster-jet target chamber. This calls for materials in mechanical support, detectors, Very Large Scale Integrated (VLSI) electronics, connectors, cables and other signal transport devices with very low outgassing. Two auxiliary detector systems, which will operate in coincidence with CHICSi, a heavy-recoil, time-of-flight system (HR-TOF) also placed inside the target chamber and a projectile fragmentation wall (PF-WALL) located outside the chamber, have also been constructed. In total, this combined system registers more than 80% of all charged particles and fragments from typical heavy-ion reactions at energies of a few hundreds of MeV per nucleon

  10. CHICSi - a compact ultra-high vacuum compatible detector system for nuclear reaction experiments at storage rings. I. General structure, mechanics and UHV compatibility

    Energy Technology Data Exchange (ETDEWEB)

    Westerberg, L.; Avdeichikov, V.; Carlen, L.; Golubev, P.; Jakobsson, B. E-mail: bo.jakobsson@kosufy.lu.se; Rouki, C.; Siwek, A.; Veldhuizen, E.J. van; Whitlow, H.J

    2003-03-11

    CELSIUS Heavy-Ion Collision Silicon detector system (CHICSi) is a large solid angle, barrel-shaped detector system, housing up to 600 detector telescopes arranged in rotational symmetry around the beam axis. CHICSi measures charged particles and fragments from nuclear reactions. It operates at internal targets of storage rings. In order to optimize space and momentum-space coverage and minimize the low-energy detection limits, CHICSi is designed for use in ultra-high vacuum (UHV, {approx}10{sup -8} Pa) inside a cluster-jet target chamber. This calls for materials in mechanical support, detectors, Very Large Scale Integrated (VLSI) electronics, connectors, cables and other signal transport devices with very low outgassing. Two auxiliary detector systems, which will operate in coincidence with CHICSi, a heavy-recoil, time-of-flight system (HR-TOF) also placed inside the target chamber and a projectile fragmentation wall (PF-WALL) located outside the chamber, have also been constructed. In total, this combined system registers more than 80% of all charged particles and fragments from typical heavy-ion reactions at energies of a few hundreds of MeV per nucleon.

  11. Dorsal skinfold chamber models in mice

    Directory of Open Access Journals (Sweden)

    Schreiter, Jeannine

    2017-07-01

    Full Text Available Background/purpose: The use of dorsal skinfold chamber models has substantially improved the understanding of micro-vascularisation in pathophysiology over the last eight decades. It allows pathophysiological studies of vascularisation over a continuous period of time. The dorsal skinfold chamber is an attractive technique for monitoring the vascularisation of autologous or allogenic transplants, wound healing, tumorigenesis and compatibility of biomaterial implants. To further reduce the animals’ discomfort while carrying the dorsal skinfold chamber, we developed a smaller chamber (the Leipzig Dorsal Skinfold Chamber and summarized the commercial available chamber models. In addition we compared our model to the common chamber. Methods: The Leipzig Dorsal Skinfold Chamber was applied to female mice with a mean weight of 22 g. Angiogenesis within the dorsal skinfold chamber was evaluated after injection of fluorescein isothiocyanate dextran with an Axio Scope microscope. The mean vessel density within the dorsal skinfold chamber was assessed over a period of 21 days at five different time points. The gained data were compared to previous results using a bigger and heavier dorsal skinfold model in mice. A PubMed and a patent search were performed and all papers related to “dorsal skinfold chamber” from 1 of January 2006 to 31 of December 2015 were evaluated regarding the dorsal skinfold chamber models and their technical improvements. The main models are described and compared to our titanium Leipzig Dorsal Skinfold Chamber model.Results: The Leipzig Dorsal Skinfold Chamber fulfils all requirements of continuous models known from previous chamber models while reducing irritation to the mice. Five different chamber models have been identified showing substantial regional diversity. The newly elaborated titanium dorsal skinfold chamber may replace the pre-existing titanium chamber model used in Germany so far, as it is smaller and lighter

  12. Growing and analyzing biofilms in flow chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

    This unit describes the setup of flow chamber systems for the study of microbial biofilms, and methods for the analysis of structural biofilm formation. Use of flow chambers allows direct microscopic investigation of biofilm formation. The biofilms in flow chambers develop under hydrodynamic......, and disassembly and cleaning of the system. In addition, embedding and fluorescent in situ hybridization of flow chamber-grown biofilms are addressed....

  13. Wire chamber degradation at the Argonne ZGS

    International Nuclear Information System (INIS)

    Haberichter, W.; Spinka, H.

    1986-01-01

    Experience with multiwire proportional chambers at high rates at the Argonne Zero Gradient Synchrotron is described. A buildup of silicon on the sense wires was observed where the beam passed through the chamber. Analysis of the chamber gas indicated that the density of silicon was probably less than 10 ppM

  14. Simple Cloud Chambers Using Gel Ice Packs

    Science.gov (United States)

    Kamata, Masahiro; Kubota, Miki

    2012-01-01

    Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry…

  15. Sensitivity of gaseous xenon ionisation chambers (1961)

    International Nuclear Information System (INIS)

    Schuhl, C.

    1960-01-01

    It seems advantageous to fill an ionization chamber with xenon gas when this chamber is used for measuring a low intensity and high energy electron or positron beam, or monitoring a gamma beam. In the study of 5 to 50 MeV electrons, xenon allows for the ionization chamber yield, an improvement of a factor 4,5. (author) [fr

  16. Proportional chambers and multiwire drift chambers at high rates

    International Nuclear Information System (INIS)

    Walenta, A.H.

    1977-01-01

    The high event and particle rates expected for ISABELLE intersecting storage rings raise the question whether PWC's and drift chambers, now widely in use in experiments, still can operate under such conditions. Various effects depend on the number of avalanches produced per length of wire N and the size of the avalanche Q, i.e., on the number of positive ions created in an avalanche. Therefore the important parameter for the following discussion is the product QN. The minimum Q is determined by the type and noise level of preamplifiers used. Examples are given for a typical low noise amplifier as well as for a typical integrated ''cheap'' amplifier. The rate/wire length N depends on the chamber arrangement, wire spacing, etc. In multiwire drift chambers, a single wire shows space-charge effects reducing the pulse height by 1% at a rate of N = 7 x 10 3 mm -1 sec -1 . At a rate of N approximately equal to 10 5 mm -1 sec -1 an efficiency loss of the order of 1% was noticed. The aging effect due to deposits on the anode wire can be reduced using low noise amplifiers and low gas gain to such an extent that a lifetime of about half a year at ISABELLE can be expected. The use of conventional cheap preamplifiers will result in a typical lifetime of about 30 days. Improvements are probable. The time resolution of Δt/sub r/ = 4 nsec fwhm seems adequate for event rates of 10 7 sec -1 . The memory time Δt/sub m/ greater than or equal to 100 nsec may cause serious problems for pattern recognition depending on layout and readout. The use of induced signals on cathode pads, thus reading out shorter parts of the wire, can solve the problem

  17. Light particle emission measurements in heavy ion reactions. Final report, June 1, 1981-May 31, 1984

    International Nuclear Information System (INIS)

    Petitt, G.A.

    1984-01-01

    Progress in instrumentation development reported includes improvements in the design of position sensitive neutron detectors, design of a thin-walled, spherical, aluminum target chamber, and use of thin silicon detectors to detect and identify evaporation residues from fusion reactions. The problem of the short lifetime of evaporation residue detectors is addressed by using a pair of large area, multi-wire proportional counters followed by a thin sheet of plastic scintillator. Neutron emission associated with fission has been studied, as well as nonequilibrium emission associated with inelastic products and evaporation residue. An experiment was performed to study neutron emission associated with fission and fission-like events in the case of the Er composite system. Other work in progress includes neutron emissions from the C + Gd and Ne + Nd reactions. 9 refs

  18. Experimental Studies on Wave Interactions of Partially Perforated Wall under Obliquely Incident Waves

    Directory of Open Access Journals (Sweden)

    Jong-In Lee

    2014-01-01

    Full Text Available This study presents wave height distribution in terms of stem wave evolution phenomena on partially perforated wall structures through three-dimensional laboratory experiments. The plain and partially perforated walls were tested to understand their effects on the stem wave evolution under the monochromatic and random wave cases with the various wave conditions, incident angle (from 10 to 40 degrees, and configurations of front and side walls. The partially perforated wall reduced the relative wave heights more effectively compared to the plain wall structure. Partially perforated walls with side walls showed a better performance in terms of wave height reduction compared to the structure without the side wall. Moreover, the relative wave heights along the wall were relatively small when the relative chamber width is large, within the range of the chamber width in this study. The wave spectra showed a frequency dependency of the wave energy dissipation. In most cases, the existence of side wall is a more important factor than the porosity of the front wall in terms of the wave height reduction even if the partially perforated wall was still effective compared to the plain wall.

  19. An open-flow pulse ionization chamber for alpha spectrometry of large-area samples

    International Nuclear Information System (INIS)

    Johansson, L.; Roos, B.; Samuelsson, C.

    1992-01-01

    The presented open-flow pulse ionization chamber was developed to make alpha spectrometry on large-area surfaces easy. One side of the chamber is left open, where the sample is to be placed. The sample acts as a chamber wall and therby defeins the detector volume. The sample area can be as large as 400 cm 2 . To prevent air from entering the volume there is a constant gas flow through the detector, coming in at the bottom of the chamber and leaking at the sides of the sample. The method results in good energy resolution and has considerable applicability in the retrospective radon research. Alpha spectra obtained in the retrospective measurements descend from 210 Po, built up in the sample from the radon daughters recoiled into a glass surface. (au)

  20. Measurement of radon concentration in air employing Lucas chamber; Pomiar koncentracji radonu za pomoca komory Lucasa

    Energy Technology Data Exchange (ETDEWEB)

    Machaj, B.

    1997-12-31

    The results of investigations aimed to determine the main features of radon concentration gauge in air, employing 0.17 L Lucas chamber, and air sample forced by an air pump are presented. For two hour sampling and measuring cycle time the dynamic error in the worst case (first read out) equals 5 % relative to the step jump of radon concentration. This is due to the increase of activity of the decay products in the chamber. It was observed that the short lived radon decay products (Po-218, Pb-214, Bi-214) are depositing on the walls of the chamber and they are not removed by flushing the chamber with air. (author). 4 refs, 19 figs, 2 tabs.

  1. Monitoring tritium in air containing other beta-emitters using ion chambers

    International Nuclear Information System (INIS)

    Jalbert, R.A.

    1975-01-01

    A flow-through ionization chamber instrument is described which is capable of measuring tritium in air containing high concentrations of other beta emitters. The instrument employs a separate concentric chamber with a thin common wall opaque only to tritium betas. Currents produced in the two chambers are subtracted leaving only the current due to tritium. With a 1.6-l sampling chamber and an 18-s time constant, tritium concentrations of 10 -6 μCi/ml to 10 -4 μCi/ml are measured with 2 sigma confidence in background beta concentrations of 4 x 10 -5 μCi/ml to 0.4 muCi/ml, respectively. (auth)

  2. Evaluation of 1,3,5 trimethylbenzene degradation in the detailed tropospheric chemistry mechanism, MCMv3.1, using environmental chamber data

    Directory of Open Access Journals (Sweden)

    A. Metzger

    2008-11-01

    Full Text Available The degradation mechanism of 1,3,5-trimethyl- benzene (TMB as implemented in the Master Chemical Mechanism version 3.1 (MCM was evaluated using data from the environmental chamber at the Paul Scherrer Institute. The results show that the MCM provides a consistent description of the photo-oxidation of TMB/NOx mixtures for a range of conditions. In all cases the agreement between the measurement and the simulation decreases with decreasing VOC-NOx ratio and in addition with increasing precursor concentration. A significant underestimation of the decay rate of TMB and thus underestimation of reactivity in the system, consistent with results from previous appraisals of the MCM, was observed.

    Much higher nitrous acid (HONO concentrations compared to simulations and expected from chamber characterization experiments were measured during these smog chamber experiments. A light induced NO2 to HONO conversion at the chamber walls is suggested to occur. This photo-enhanced NO2 to HONO conversion with subsequent HONO photolysis enhances the reactivity of the system. After the implementation of this reaction in the model it describes the decay of TMB properly. Nevertheless, the model still over-predicts ozone at a later stage of the experiment. This can be attributed to a too slow removal of NO2. It is also shown that this photo-enhanced HONO formation is not restricted to TMB photo-oxidation but also occurs in other chemical systems (e.g. α-pinene. However, the influence of HONO as a source of OH radicals is less important in these more reactive systems and therefore the importance of the HONO chemistry is less obvious.

  3. Optimization of spherical ionization chambers for neutron diagnostics in Tokamak plants

    International Nuclear Information System (INIS)

    Hoenen, F.

    1983-05-01

    For the investigation of neutron emission from fusion plasmas Pulse-Ion-Chamber are favored because of their high temporal resolution, the availability of results immedately after the discharge and their insensitivity to hard X-rays. However to measure ion temperatures below 2 keV with the aid of neutron spectroscopy the detectors have to be improved. Difficulties arise from the fact that in Pulse-Ion-Chambers the pulse height is a function of the position in the chamber where the ion pairs are produced (Induction effect). It will be shown that the induction effect is smaller in spherical ionisation chambers than in cylindrical ones. This means an increase in energy resolution so that neutrons from the D(D,n) 3 He reaction can be analysed with an energy resolution of better than 3% in spherical chambers. (orig./HP) [de

  4. Evaluation of ozone generation and indoor organic compounds removal by air cleaners based on chamber tests

    Science.gov (United States)

    Yu, Kuo-Pin; Lee, Grace Whei-May; Hsieh, Ching-Pei; Lin, Chi-Chi

    2011-01-01

    Ozone can cause many health problems, including exacerbation of asthma, throat irritation, cough, chest ache, shortness of breath, and respiratory infections. Air cleaners are one of the sources of indoor ozone, and thus the evaluation of ozone generated by air cleaners is desired significant issue. Most evaluation methods proposed are based on chamber tests. However, the adsorption and desorption of ozone on the wall of test chamber and the deposition of ozone resulted from the surface reaction can influence the evaluation results. In this study, we developed a mass balance model that took the adsorption, desorption and deposition of ozone into consideration to evaluate the effective ozone emission rates of six selected air cleaners. The experiments were conducted in a stainless steel chamber with a volume of 11.3 m 3 at 25 °C and 60% relative humidity. The adsorption, desorption and deposition rate constants of ozone obtained by fitting the model to the experimental data were k a = 0.149 ± 0.052 m h -1, k d = 0.013 ± 0.007 h -1, and k r = 0.050 ± 0.020 h -1, respectively. The effective ozone emission rates of Air Cleaners No. 1, 2, and 3 ranged between 13,400-24,500 μg h -1, 7190-10,400 μg h -1, and 4880-6560 μg h -1, respectively, which were more stable than those of No.4, 5, and 6. The effective ozone emission rates of Air Cleaners No. 4, 5, and 6 increased with the time of operation which might be relevant to the decrease of ozone removal by the "aging" filter installed in these cleaners. The removal of toluene and formaldehyde by these six air cleaners were also evaluated and the clean air delivery rates (CADRs) of these two pollutants ranged from non-detectable to 0.42 ± 0.08 m 3 h -1, and from non-detectable to 0.75 ± 0.07 m 3 h -1, respectively. The CADRs showed an insignificant relationship with the effective ozone emission rates. Thus, the removal of toluene and formaldehyde might be resulted from the adsorption on the filters and the

  5. Molecular beam mass spectrometer equipped with a catalytic wall reactor for in situ studies in high temperature catalysis research

    International Nuclear Information System (INIS)

    Horn, R.; Ihmann, K.; Ihmann, J.; Jentoft, F.C.; Geske, M.; Taha, A.; Pelzer, K.; Schloegl, R.

    2006-01-01

    A newly developed apparatus combining a molecular beam mass spectrometer and a catalytic wall reactor is described. The setup has been developed for in situ studies of high temperature catalytic reactions (>1000 deg. C), which involve besides surface reactions also gas phase reactions in their mechanism. The goal is to identify gas phase radicals by threshold ionization. A tubular reactor, made from the catalytic material, is positioned in a vacuum chamber. Expansion of the gas through a 100 μm sampling orifice in the reactor wall into differentially pumped nozzle, skimmer, and collimator chambers leads to the formation of a molecular beam. A quadrupole mass spectrometer with electron impact ion source designed for molecular beam inlet and threshold ionization measurements is used as the analyzer. The sampling time from nozzle to detector is estimated to be less than 10 ms. A detection time resolution of up to 20 ms can be reached. The temperature of the reactor is measured by pyrometry. Besides a detailed description of the setup components and the physical background of the method, this article presents measurements showing the performance of the apparatus. After deriving the shape and width of the energy spread of the ionizing electrons from measurements on N 2 and He we estimated the detection limit in threshold ionization measurements using binary mixtures of CO in N 2 to be in the range of several hundreds of ppm. Mass spectra and threshold ionization measurements recorded during catalytic partial oxidation of methane at 1250 deg. C on a Pt catalyst are presented. The detection of CH 3 · radicals is successfully demonstrated

  6. Molecular beam mass spectrometer equipped with a catalytic wall reactor for in situ studies in high temperature catalysis research

    Science.gov (United States)

    Horn, R.; Ihmann, K.; Ihmann, J.; Jentoft, F. C.; Geske, M.; Taha, A.; Pelzer, K.; Schlögl, R.

    2006-05-01

    A newly developed apparatus combining a molecular beam mass spectrometer and a catalytic wall reactor is described. The setup has been developed for in situ studies of high temperature catalytic reactions (>1000°C), which involve besides surface reactions also gas phase reactions in their mechanism. The goal is to identify gas phase radicals by threshold ionization. A tubular reactor, made from the catalytic material, is positioned in a vacuum chamber. Expansion of the gas through a 100μm sampling orifice in the reactor wall into differentially pumped nozzle, skimmer, and collimator chambers leads to the formation of a molecular beam. A quadrupole mass spectrometer with electron impact ion source designed for molecular beam inlet and threshold ionization measurements is used as the analyzer. The sampling time from nozzle to detector is estimated to be less than 10ms. A detection time resolution of up to 20ms can be reached. The temperature of the reactor is measured by pyrometry. Besides a detailed description of the setup components and the physical background of the method, this article presents measurements showing the performance of the apparatus. After deriving the shape and width of the energy spread of the ionizing electrons from measurements on N2 and He we estimated the detection limit in threshold ionization measurements using binary mixtures of CO in N2 to be in the range of several hundreds of ppm. Mass spectra and threshold ionization measurements recorded during catalytic partial oxidation of methane at 1250°C on a Pt catalyst are presented. The detection of CH3• radicals is successfully demonstrated.

  7. Chamber propagation physics for heavy ion fusion

    International Nuclear Information System (INIS)

    Callahan, D.A.

    1995-01-01

    Chamber transport is an important area of study for heavy ion fusion. Final focus and chamber-transport are high leverage areas providing opportunities to significantly decrease the cost of electricity from a heavy ion fusion power plant. Chamber transport in two basic regimes is under consideration. In the low chamber density regime (approx-lt 0.003 torr), ballistic or nearly-ballistic transport is used. Partial beam neutralization has been studied to offset the effects of beam stripping. In the high chamber density regime (approx-gt.1 torr), two transport modes (pinched transport and channel transport) are under investigation. Both involve focusing the beam outside the chamber then transporting it at small radius (∼ 2 mm). Both high chamber density modes relax the constraints on the beam quality needed from the accelerator which will reduce the driver cost and the cost of electricity

  8. Chamber propagation physics for heavy ion fusion

    International Nuclear Information System (INIS)

    Callahan, D.A.

    1996-01-01

    Chamber transport is a key area of study for heavy ion fusion. Final focus and chamber transport are high leverage areas providing opportunities to decrease significantly the cost of electricity from a heavy ion fusion power plant. Chamber transport in two basic regimes is under consideration. In the low chamber density regime (below about 0.003 Torr), ballistic or nearly ballistic transport is used. Partial beam neutralization has been studied to offset the effects of beam stripping. In the high chamber density regime (above about 0.1 Torr), two transport modes (pinched transport and channel transport) are under investigation. Both involve focusing the beam outside the chamber and then transporting it at small radius (about 2 mm). Both high chamber density modes relax the constraints on the beam quality needed from the accelerator which will reduce the driver cost and the cost of electricity. (orig.)

  9. Loss of ions in cavity ionization chambers

    International Nuclear Information System (INIS)

    Takata, N.; Tran, N.T.; Kim, E.; Marsoem, P.; Kurosawa, T.; Koyama, Y.

    2005-01-01

    Ion losses due to initial recombination, volume recombination, and back diffusion were each determined by measurements and calculations for different size cylindrical ionization chambers and spherical ionization chambers. By measuring signal currents from these ionization chambers irradiated with 60 Co gamma rays, two groups of ion losses were obtained. (Group 1) Ion loss due to initial recombination and diffusion, which changes proportionally to the inverse of the voltage applied to the ionization chambers; (and group 2) ion loss due to volume recombination, which changes proportionally to the inverse of the square of the applied voltage. The diffusion loss was obtained separately by computing electric field distributions in the ionization chambers. It was found that diffusion loss is larger than initial recombination loss for the cylindrical ionization chambers and vise versa for the spherical ionization chambers

  10. TRU waste characterization chamber gloveboxes

    International Nuclear Information System (INIS)

    Duncan, D. S.

    1998-01-01

    Argonne National Laboratory-West (ANL-W) is participating in the Department of Energy's (DOE) National Transuranic Waste Program in support of the Waste Isolation Pilot Plant (WIPP). The Laboratory's support currently consists of intrusive characterization of a selected population of drums containing transuranic waste. This characterization is performed in a complex of alpha containment gloveboxes termed the Waste Characterization Gloveboxes. Made up of the Waste Characterization Chamber, Sample Preparation Glovebox, and the Equipment Repair Glovebox, they were designed as a small production characterization facility for support of the Idaho National Engineering and Environmental Laboratory (INEEL). This paper presents salient features of these gloveboxes

  11. Experimental work on drift chambers

    International Nuclear Information System (INIS)

    Alcaraz, J.; Duran, I.; Gonzalez, E.; Martinez-Laso, L.; Olmos, P.

    1989-01-01

    An experimental work made on drift chambers is described in two chapters. In the firt chapter we present the description of the experimental installation used, as well as some details on the data adquisition systems and the characteristics on three ways used for calibration proposes (cosmic muons, β radiation and test beam using SPS at CERN facilities). The second chapter describes the defferent prototypes studied. The experimental set up and the analysis are given. Some results are discussed. The magnetic field effect is also studied. (Author)

  12. Nova target chamber decontamination study

    International Nuclear Information System (INIS)

    1979-05-01

    An engineering study was performed to determine the most effective method for decontamination of the Nova target chamber. Manual and remote decontamination methods currently being used were surveyed. In addition, a concept that may not require in-situ decontamination was investigated. Based on the presently available information concerning material and system compatibility and particle penetration, it is recommended that a system of removable aluminum shields be considered. It is also recommended that a series of tests be performed to more precisely determine the vacuum compatibility and penetrability of other materials discussed in this report

  13. Gnathostomiasis of the anterior chamber

    Directory of Open Access Journals (Sweden)

    Barua P

    2007-01-01

    Full Text Available Ocular involvement with Gnathostoma spinigerum occurs years after the initial infection that is acquired by ingestion of poorly cooked, pickled seafood or water contaminated with third stage larvae. Here we report a case of gnathostomiasis of the left eye of a 32-year-old lady hailing from Meghalaya, India. Her vision had deteriorated to hand movement. Slit lamp examination revealed a live, actively motile worm in the anterior chamber, which was extracted by supra temporal limbal incision and visual acuity was restored.

  14. Predictive factors for anterior chamber fibrin formation after vitreoretinal surgery

    Directory of Open Access Journals (Sweden)

    Leonardo Provetti Cunha

    2014-04-01

    Full Text Available Purpose: The aim of this study was to investigate possible predictive factors related to anterior chamber fibrin formation after vitreoretinal surgery in a large series of patients. Methods: The data of 185 eyes of 185 patients submitted to vitreoretinal surgery was reviewed. The following variables were evaluated: the postoperatively presence of fibrin, age, diabetes mellitus, the vitrectomy system gauge (20, 23 or 25 gauge, the type of vitreous substitute, the influence of prior surgical procedures and the combination with cataract extraction. To evaluate predictive factors for anterior chamber fibrin formation, univariate analysis was performed. A multivariate stepwise logistic regression model was adjusted to investigate factors associated with fibrin formation (p<0.05. Results: Fibrinoid anterior chamber reaction was found in 12 (6.4% patients. For multivariate logistic regression analysis, balanced salt solution (BSS, the chance of fibrin occurrence was 5 times greater (odds ratio 4.83, CI 95% 1.302 - 17.892; p=0.019, while combination with phacoemulsification increased the chance of fibrin formation by 20 times (odds ratio 20, CI 95% 2.480 - 161.347; p=0.005. No significant difference was found regarding other variables. Conclusion: Anterior chamber fibrin formation is an unwanted complication after vitreoretinal surgery. Factors such as combined performance of phacoemulsification and the use of balanced salt solution as a vitreous substitute may predispose the occurrence of this complication.

  15. The chemical kinetics of the reactions of lithium with steam-air mixtures

    International Nuclear Information System (INIS)

    Barnett, D.S.; Kazimi, M.S.

    1989-04-01

    This work involved the experimental and analytical determination of the consequences of lithium fires in the presence of steam. Experiments were performed to characterize the chemical reactions of lithium with steam-nitrogen and steam-air mixtures. Models were introduced in the LITFIRE code to describe lithium fires in the presence of steam inside the containment building and plasma chamber of a hypothetical fusion reactor. The code was also equipped with the capability to determine the effects of decay heat and lithium fire on the temperature response of the reactor first wall in the event of a coolant disturbance. Forty-two kinetics experiments were performed in which a stream of steam-nitrogen or steam-air was passed over and reacted with approximately three grams of lithium heated to a predetermined temperature. The lithium reaction rates with the constituent gases were measured and characterized for a wide range of lithium temperatures and gas compositions. Experiments were performed with steam molar concentrations of 5, 15 and 30% and lithium temperatures ranging from 400 to 1100 degree C, inclusive. The LITFIRE code was modified to enable it to model the interactions of lithium with steam-air atmospheres. Results of the reaction kinetics experiments were used in the reaction model, and the heat transfer model was expanded to allow it to handle condensible atmospheres. Three groups of accidents were investigated: a spill on the containment building floor, a spill inside the reactor plasma chamber, and a spill inside the plasma chamber with steam injection to the containment building simulating a steam line break. The results were compared to dry air cases under the same conditions. 23 refs., 66 figs., 18 tabs

  16. Modeling of heat transfer in wall-cooled tubular reactors

    NARCIS (Netherlands)

    Koning, G.W.; Westerterp, K.R.

    1999-01-01

    In a pilot scale wall-cooled tubular reactor, temperature profiles have been measured with and without reaction. As a model reaction oxidation of carbon monoxide in air over a copper chromite catalyst has been used. The kinetics of this reaction have been determined separately in two kinetic

  17. High concentration tritium gas measurement with small volume ionization chambers for fusion fuel gas monitors

    International Nuclear Information System (INIS)

    Uda, Tatsuhiko; Okuno, Kenji; Matsuda, Yuji; Naruse, Yuji

    1991-01-01

    To apply ionization chambers to fusion fuel gas processing systems, high concentration tritium gas was experimentally measured with small volume 0.16 and 21.6 cm 3 ionization chambers. From plateau curves, the optimum electric field strength was obtained as 100∼200 V/cm. Detection efficiency was confirmed as dependent on the ionization ability of the filled gas, and moreover on its stopping power, because when the range of the β-rays was shortened, the probability of energy loss by collisions with the electrode and chamber wall increased. Loss of ions by recombination was prevented by using a small volume ionization chamber. For example the 0.16 cm 3 ionization chamber gave measurement with linearity to above 40% tritium gas. After the tritium gas measurements, the concentration levels inside the chamber were estimated from their memory currents. Although more than 1/4,000 of the maximum, current was observed as a memory effect, the smaller ionization chamber gave a smaller memory effect. (author)

  18. Dosimetry with tissue-equivalent ionisation chambers in fast neutron fields for biomedical applications

    International Nuclear Information System (INIS)

    Zoetelief, J.; Broerse, J.J.

    1983-01-01

    The use of calibrated tissue-equivalent (TE) ionisation chambers is commonly considered to be the most practical method for total absorbed dose determinations in mixed neutron-photon fields for biomedical applications. The total absorbed dose can be derived from the charge produced within the cavity of an ionisation chamber employing a number of physical parameters. To arrive at the charge produced in the cavity several correction factors have to be introduced which are related to the operational characteristics of the chambers. Information on the operational characteristics of four TE ionisation chambers is presented in relation to ion collection, density and composition of gas in the cavity, wall thickness and effective point of measurement. In addition, some recent results from an ionisation chamber operated at high gas pressures are presented. The total absorbed doses derived from TE ionisation chambers show agreement within the uncertainty limits with results from other independent dosimetry methods, i.e., differential fluence measurements and a TE calorimeter. Conscientious experimentation and a common data base can provide dosimetry results with TE ionisation chambers with variations of less than +-2%. (author)

  19. A more modern look for the Council Chamber exhibition

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    When the Council Chamber was renovated, the old photographs displayed on the walls were taken down... they've now been replaced by new panels printed on Plexiglas. The theme of the exhibition is still the history of CERN, but it now features the very latest from graphic design. Fabienne Marcastel, who designed it, tells us more. Two of the new panels recently installed in the Council Chamber. The presentation is simple and elegant. The content is based essentially on the accelerators and the aim of the graphic design is not to attract the public's attention to the panels but rather to provide a pleasant décor for the Chamber's users. "The old photographs stopped at the LEP. The new panels show the history of CERN but also what the Laboratory is like today. Visually, the plan is the starting point, the key to understanding how CERN has changed. It shows how CERN occupies the land it is built on," explains Fabienne Marcastel, the exhibition's graphic designer. The four panels a...

  20. Characterisation of the photolytic HONO-source in the atmosphere simulation chamber SAPHIR

    Directory of Open Access Journals (Sweden)

    F. Rohrer

    2005-01-01

    Full Text Available HONO formation has been proposed as an important OH radical source in simulation chambers for more than two decades. Besides the heterogeneous HONO formation by the dark reaction of NO2 and adsorbed water, a photolytic source has been proposed to explain the elevated reactivity in simulation chamber experiments. However, the mechanism of the photolytic process is not well understood so far. As expected, production of HONO and NOx was also observed inside the new atmospheric simulation chamber SAPHIR under solar irradiation. This photolytic HONO and NOx formation was studied with a sensitive HONO instrument under reproducible controlled conditions at atmospheric concentrations of other trace gases. It is shown that the photolytic HONO source in the SAPHIR chamber is not caused by NO2 reactions and that it is the only direct NOy source under illuminated conditions. In addition, the photolysis of nitrate which was recently postulated for the observed photolytic HONO formation on snow, ground, and glass surfaces, can be excluded in the chamber. A photolytic HONO source at the surface of the chamber is proposed which is strongly dependent on humidity, on light intensity, and on temperature. An empirical function describes these dependencies and reproduces the observed HONO formation rates to within 10%. It is shown that the photolysis of HONO represents the dominant radical source in the SAPHIR chamber for typical tropospheric O3/H2O concentrations. For these conditions, the HONO concentrations inside SAPHIR are similar to recent observations in ambient air.

  1. Physicist makes muon chamber sing

    CERN Multimedia

    2007-01-01

    This Monitored Drift Tube detector, consisting of argon-CO2-filled aluminium tubes with a wire down the centre of each, will track muons in ATLAS; Tiecke used a single tube from one of these detectors to create the pipes in his organ. Particle physicists can make good musicians; but did you know particle detectors can make good music? That's what NIKHEF physicist Henk Tiecke learned when he used pipes cut from the ATLAS Monitored Drift Tube detector (MDT) to build his own working Dutch-style barrel organ in the autumn of 2005. 'I like to work with my hands,' said Tiecke, who worked as a senior physicist at NIKHEF, Amsterdam, on ZEUS until his retirement last summer. Tiecke had already constructed his barrel organ when he visited some colleagues in the ATLAS muon chambers production area at Nikhef in 2005. He noticed that the aluminium tubes they were using to build the chambers were about three centimetres in diameter-just the right size for a pipe in a barrel organ. 'The sound is not as nice as from wooden...

  2. Laboratory investigations of the alpha-pinene/ozone gas-phase reaction

    International Nuclear Information System (INIS)

    Benner, C.L.

    1985-01-01

    In order to provide more insight into terpene photooxidation or ozonolysis reaction mechanisms, a radiotracer technique was developed. This technique was applied to an investigation of the 14 C-alpha-pinene/ozone reaction. In the first phase of the research, the carbon distribution at the conclusion of the ozonolysis reaction was determined by separating carbon-14-labelled gaseous products from labelled aerosols, and counting each phase by liquid scintillation methods. The resulting carbon balance was 38% to 60% filtered aerosols, 6% to 20% gas phase compounds, and 11% to 29% products absorbed on the reaction chamber walls. Recoveries of the alpha-pinene carbon-14 ranging from 79% to 97% were achieved using this method. The alpha-pinene concentrations in these experiments were close to ambient (1 part per billion), yet the carbon balance was similar to that observed at much higher concentrations (>1 part per million). In the second phase of the alpha-pinene study, both gas and aerosol products of the ozonolysis reaction were collected on cartridges impregnated with 2,4-dinitrophenylhydrazine, then analyzed by HPLC. In the final experiments, alpha-pinene aerosol was reacted with a silylating agent to improve the detection of organic acids and alcohols. The gas chromatographic/mass spectrometric analysis of the silylated aerosol products showed evidence of dimer/polymer formation occurring in the ozonolysis reaction

  3. Basic Aerodynamics of Combustion Chambers,

    Science.gov (United States)

    1981-05-20

    v.t.r . 7- ;t ifr n.- ±.n’-r s- e cf"’..a c.-t-"li-& , t:- ., ’-., - e’ .. ~ -*..~ - z. ~~ v.’hich the contour liner a- : 7 7- 7....-- ---------- - the...and 0,. G G- GAAp d- A’P*( - 4,) [kg/s 1, (4.69) he flow function 𔃾,o; which corresnonds to the flow line which matches the solid surface of +he wall is

  4. RETAINED STONE PIECE IN ANTERIOR CHAMBER

    Directory of Open Access Journals (Sweden)

    ZvornicaninJasmin, Nadarevic-VodencarevicAmra

    2015-04-01

    Full Text Available ABSTRACT We read with interest the article by Surekha et al. regarding the retained stone piece in anterior chamber. Similar to the results of previous studies, the authors found that delayed intraocular foreign body (IOFB management can result in good visual outcome without an apparent increased risk of endophthalmitis or other deleterious side effects. However, the authors failed to explain the exact reason for the diminution of vision in patients left eye. It is unclear what the uncorrected visual acuity was and what kind of correction was used, more precisely type and amount of cylinder, given the presence of the corneal opacity. Since the size of the IOFB is approximately 4x4x1mm, significant irido-corneal angle changes resulting in intraocular pressure raise and optic nerve head damage can be expected. Traumatic glaucoma following open globe injury can occur in 2.7 to 19% of cases, with several risk factors associated with glaucoma development (advanced age, poor visual acuity at presentation,perforating rather than penetrating ocular injury,lens injury, presence of vitreous hemorrhage and presence of an IOFB. Earlier reportsof latetraumaticoptic neuropathy onset, even after several years, indicate that this possibility cannot be completely ruled out too. Therefore, repeated intraocular pressure measurements, gonioscopy, pupillary reaction assessment, together with through posterior segment examination including visual field and optical coherence tomography examinations can be useful in determining the possible optic nerve damage as one of the possible reasons for visual acuity reduction. The authors did not suggest any operative treatment at this time. However, it should bear in mind that the inert anterior chamber IOFB could be a risk factor for non-infectious endophthalmitis development even after many years. Also, long term retained anterior chamber foreign body leads to permanent endothelial cell loss and can even result in a corneal

  5. Flux measurements with a sniffer probe near the wall in ASDEX

    International Nuclear Information System (INIS)

    Poschenrieder, W.; Venus, G.; Wang, Y.G.; Mueller, E.R.; Bartiromo, R.; Becker, G.; Bosch, H.S.; Brocken, H.; Eberhagen, A.; Fussmann, G.; Gehre, O.; Gernhardt, J.; Gierke, G. v.; Glock, E.; Gruber, O.; Haas, G.; Janeschitz, G.; Karger, F.; Kotze, P.B.; Keilhacker, M.; Klueber, O.; Kornherr, M.; Lackner, K.; Lenoci, M.; Lisitano, G.; Mayer, H.M.; McCormick, K.; Meisel, D.; Mertens, V.; Murmann, H.; Niedermeyer, H.; Rapp, H.; Roehr, H.; Ryter, F.; Schneider, F.; Siller, G.; Smeulders, P.; Soeldner, F.; Speth, E.; Steuer, K.H.; Vollmer, O.; Wagner, F.

    1985-01-01

    For a detailed assessment of particle recycling in a tokamak it is necessary to know quality and quantity of the particle fluxes directed to the elements of the wall. In a divertor machine like ASDEX we have to differentiate between at least four distinct elements: main chamber wall, protective limiters, collector plates, and divertor walls. Relevant data about the divertor region are obtained from pressure and flux measurements. (orig./GG)

  6. The effect of build-up cap materials on the response of an ionization chamber to 60Co gamma rays

    International Nuclear Information System (INIS)

    Rocha, M.P.O.; Almeida, C.E. de

    1993-01-01

    Knowledge of the effect of wall and build-up cap materials on ionization chamber response is necessary to determine absorbed dose in a medium using a calibration factor based on exposure or kerma in air. Attenuation and scattering effects of 60 Co gamma rays in the ionization chamber wall and build-up cap, as well as their non-equivalence to air, were studied with an OFS ionization chamber (Delrin wall) and a set of build-up caps specially built for this purpose. Results for a specific material were plotted as functions of wall and cap total thickness, extrapolated to zero wall thickness, then corrected for mean centre of electron production in the wall (= 0.136 g cm -2 ). Correction factors for a specific thickness were analysed in relation to cap material, and to relative responses compared with values calculated by using AAPM, SEFM and IAEA formalisms for cap effects. A Monte Carlo calculation was performed to compare the experimental and theoretical values. Calculations showed an agreement within 0.1% with experimental values and a wall effect of approximately 1.6%. (Author)

  7. Determination of non-uniformity correction factors for cylindrical ionization chambers close to 192Ir brachytherapy sources

    International Nuclear Information System (INIS)

    Toelli, H.; Bielajew, A. F.; Mattsson, O.; Sernbo, G.

    1995-01-01

    When ionization chambers are used in brachytherapy dosimetry, the measurements must be corrected for the non-uniformity of the incident photon fluence. The theory for determination of non-uniformity correction factors, developed by Kondo and Randolph (Rad. Res. 1960) assumes that the electron fluence within the air cavity is isotropic and does not take into account material differences in the chamber wall. The theory was extended by Bielajew (PMB 1990) using an anisotropic electron angular fluence in the cavity. In contrast to the theory by Kondo and Randolph, the anisotropic theory predicts a wall material dependence in the non-uniformity correction factors. This work presents experimental determination of non-uniformity correction factors at distances between 10 and 140 mm from an Ir-192 source. The experimental work makes use of a PTW23331-chamber and Farmer-type chambers (NE2571 and NE2581) with different materials in the walls. The results of the experiments agree well with the anisotropic theory. Due to the geometrical shape of the NE-type chambers, it is shown that the full length of the these chambers, 24.1mm, is not an appropriate input parameter when theoretical non-uniformity correction factors are evaluated

  8. A Facility for Long-Term Mars Simulation Experiments: The Mars Environmental Simulation Chamber (MESCH)

    Science.gov (United States)

    Jensen, Lars Liengaard; Merrison, Jonathan; Hansen, Aviaja Anna; Mikkelsen, Karina Aarup; Kristoffersen, Tommy; Nørnberg, Per; Lomstein, Bente Aagaard; Finster, Kai

    2008-06-01

    We describe the design, construction, and pilot operation of a Mars simulation facility comprised of a cryogenic environmental chamber, an atmospheric gas analyzer, and a xenon/mercury discharge source for UV generation. The Mars Environmental Simulation Chamber (MESCH) consists of a double-walled cylindrical chamber. The double wall provides a cooling mantle through which liquid N2 can be circulated. A load-lock system that consists of a small pressure-exchange chamber, which can be evacuated, allows for the exchange of samples without changing the chamber environment. Fitted within the MESCH is a carousel, which holds up to 10 steel sample tubes. Rotation of the carousel is controlled by an external motor. Each sample in the carousel can be placed at any desired position. Environmental data, such as temperature, pressure, and UV exposure time, are computer logged and used in automated feedback mechanisms, enabling a wide variety of experiments that include time series. Tests of the simulation facility have successfully demonstrated its ability to produce temperature cycles and maintain low temperature (down to -140°C), low atmospheric pressure (5 10 mbar), and a gas composition like that of Mars during long-term experiments.

  9. Data acquisition system for a deuteration chamber

    International Nuclear Information System (INIS)

    Monroy A, L.

    1994-01-01

    The work present is focusing auxiliary in the experiment the reaction of fusion in cold in the laboratory of Physical of Plasmas of Instituto Nacional de Investigaciones Nucleares. These systems of acquisition of data concrete to register in line surface of pressure and temperature in the gap of 5.6 x 10 -4 to 1 x 10 3 and -270 to 1300 Centigrade degrees with help of personal computer. The manner of purchase in chamber of Deuterium is per middle of thermocouple with the object of whereas any control of the temperature in different point in the some of manner the signal of in for the system is the thermocouple (milli volts), the conversion analogy a digital is mean of Cad of 12 bits rate double slope the out is mean the PPI to send the signal to P C of these manner the read of the thermocouples is translate graphic or digital in the screen of the P C. In the phase of pressure element sensor is measure type Pirani, the measure is of manner of temperature. (Author)

  10. R3B time projection chamber

    Directory of Open Access Journals (Sweden)

    Legou P.

    2012-07-01

    Full Text Available Within the international FAIR project, the R3B collaboration (Reaction studies with Radioactive Relativistic beams will be in charge of the physics program with secondary beams of energy between 200 and 1500MeV per nucleon. Central to the R3B set-up will be a large-aperture superconducting magnet under construction at CEA-Saclay. An international collaboration has been formed to work on the design of a large time-projection chamber (TPC to be installed behind this magnet to cover the full phase-space of the charged fragments produced in the target. Within this collaboration, tests of detector prototypes were performed with the heavy-ions beams at GSI Darmstadt. These prototypes were equipped with a gaseous Micromegas detector. Two amplification technologies were tested, either conventional or resistive Micromegas and two construction concepts, bulk-Micromegas or micro-meshes screwed on the PCB. We will present the results of the last beam and the 1m TPC station which will be dedicated to make tests using the real drift distance and compare the performances of micromegas and GEM.

  11. Firefighter Nozzle Reaction

    DEFF Research Database (Denmark)

    Chin, Selena K.; Sunderland, Peter B.; Jomaas, Grunde

    2017-01-01

    Nozzle reaction and hose tension are analyzed using conservation of fluid momentum and assuming steady, inviscid flow and a flexible hose in frictionless contact with the ground. An expression that is independent of the bend angle is derived for the hose tension. If this tension is exceeded owing...... to anchor forces, the hose becomes straight. The nozzle reaction is found to equal the jet momentum flow rate, and it does not change when an elbow connects the hose to the nozzle. A forward force must be exerted by a firefighter or another anchor that matches the forward force that the jet would exert...... on a perpendicular wall. Three reaction expressions are derived, allowing it to be determined in terms of hose diameter, jet diameter, flow rate, and static pressure upstream of the nozzle. The nozzle reaction predictions used by the fire service are 56% to 90% of those obtained here for typical firefighting hand...

  12. Influence of shear on microbial adhesion to PEO-brushes and glass by convective-diffusion and sedimentation in a parallel plate flow chamber

    NARCIS (Netherlands)

    Roosjen, A; Boks, NP; van der Mei, HC; Busscher, HJ; Norde, W

    2005-01-01

    Microbial adhesion to surfaces often occurs despite high wall shear rates acting on the adhering microorganisms. In this paper, we compare the wall shear rates needed to prevent microbial adhesion to bare glass and poly(ethylene oxide) (PEO)-brush coated glass in a parallel plate flow chamber.

  13. Study of plasma in MAGO chamber by own neutron radiation

    International Nuclear Information System (INIS)

    Burenkov, O.M.; Garanin, S.F.; Demin, A.N.; Dudin, I.F.; Korchagin, V.P.; Morozov, I.V.; Mokhov, V.N.; Pavlovskij, E.S.; Chernyshev, V.K.; Yakubov, V.B.

    1996-01-01

    The measured ratio of the DD and DT reaction rates is used for determining the ion temperature in the MAGO hot plasma chamber driven by explosive magnetic generator. The method exploits the differences in the temperature dependence of the DD and DT reaction rates. The reaction rates are estimated from the DD and DT neutron spectra measured by the time-of flight method. In the paper the MAGO experimental arrangement is described in detail, and the problems arising at interpretation of the somewhat contradictory results of neutron diagnostics are discussed. A reasonable value of the ion temperature (5.5 keV maximum) can be obtained when assuming a strong anisotropy of the ion distribution. In order to verify the reported results further more detailed neutron diagnostic experiments are planned. (J.U.). 7 figs., 6 refs

  14. Study of plasma in MAGO chamber by own neutron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Burenkov, O M; Garanin, S F; Demin, A N; Dudin, I F; Korchagin, V P; Morozov, I V; Mokhov, V N; Pavlovskij, E S; Chernyshev, V K; Yakubov, V B [All-Russian Scientific Research Institute of Experimental Physics, Arzamas (Russian Federation)

    1997-12-31

    The measured ratio of the DD and DT reaction rates is used for determining the ion temperature in the MAGO hot plasma chamber driven by explosive magnetic generator. The method exploits the differences in the temperature dependence of the DD and DT reaction rates. The reaction rates are estimated from the DD and DT neutron spectra measured by the time-of flight method. In the paper the MAGO experimental arrangement is described in detail, and the problems arising at interpretation of the somewhat contradictory results of neutron diagnostics are discussed. A reasonable value of the ion temperature (5.5 keV maximum) can be obtained when assuming a strong anisotropy of the ion distribution. In order to verify the reported results further more detailed neutron diagnostic experiments are planned. (J.U.). 7 figs., 6 refs.

  15. Abdominal wall fat pad biopsy

    Science.gov (United States)

    Amyloidosis - abdominal wall fat pad biopsy; Abdominal wall biopsy; Biopsy - abdominal wall fat pad ... is the most common method of taking an abdominal wall fat pad biopsy . The health care provider cleans the ...

  16. The Role of the Spatial and Temporal Radiation Deposition in Inertial Fusion Chambers: The case of HiPER

    OpenAIRE

    Alvarez Ruiz, Jesus; Garoz Gómez, David; Gonzalez Arrabal, Raquel; Rivera de Mena, Antonio; Perlado Martín, José Manuel

    2010-01-01

    The first wall armour for the reactor chamber of HiPER will have to face short energy pulses of 5 to 20 MJ mostly in the form of x-rays and charged particles at a repetition rate of 5–10 Hz. Armour material and chamber dimensions have to be chosen to avoid/minimize damage to the chamber, ensuring the proper functioning of the facility during its planned lifetime. The maximum energy fluence that the armour can withstand without risk of failure, is determined by temporal and spatial deposition ...

  17. The role of spatial and temporal radiation deposition in inertial fusion chambers: the case of HiPER¿

    OpenAIRE

    Alvarez Ruiz, Jesus; Garoz Gómez, David; Gonzalez Arrabal, Raquel; Rivera de Mena, Antonio; Perlado Martín, José Manuel

    2011-01-01

    The first wall armour for the reactor chamber of HiPER will have to face short energy pulses of 5 to 20 MJ mostly in the form of x-rays and charged particles at a repetition rate of 5–10 Hz. Armour material and chamber dimensions have to be chosen to avoid/minimize damage to the chamber, ensuring the proper functioning of the facility during its planned lifetime. The maximum energy fluence that the armour can withstand without risk of failure, is determined by temporal and spatial deposition of...

  18. Venturi vacuum systems for hypobaric chamber operations.

    Science.gov (United States)

    Robinson, R; Swaby, G; Sutton, T; Fife, C; Powell, M; Butler, B D

    1997-11-01

    Physiological studies of the effects of high altitude on man often require the use of a hypobaric chamber to simulate the reduced ambient pressures. Typical "altitude" chambers in use today require complex mechanical vacuum systems to evacuate the chamber air, either directly or via reservoir system. Use of these pumps adds to the cost of both chamber procurement and maintenance, and service of these pumps requires trained support personnel and regular upkeep. In this report we describe use of venturi vacuum pumps to perform the function of mechanical vacuum pumps for human and experimental altitude chamber operations. Advantages of the venturi pumps include their relatively low procurement cost, small size and light weight, ease of installation and plumbing, lack of moving parts, and independence from electrical power sources, fossil fuels and lubricants. Conversion of three hyperbaric chambers to combined hyper/hypobaric use is described.

  19. Proportional chamber with data analog output

    International Nuclear Information System (INIS)

    Popov, V.E.; Prokof'ev, A.N.

    1977-01-01

    A proportional multiwier chamber is described. The chamber makes it possible to determine angles at wich a pion strikes a polarized target. A delay line, made of 60-core flat cable is used for removing signals from the chamber. From the delay line, signals are amplified and successively injected into shapers and a time-to-amplitude converter. An amplitude of the time-to amplitude converter output signal unambiguously determines the coordinate of a point at which a particle strikes the chamber plane. There are also given circuits of amplifiers, which consist of a preamplifier with gain 30 and a main amplifier with adjustable gain. Data on testing the chamber with the 450 MeV pion beam is demonstrated. The chamber features an efficiency of about 98 per cent under load of 2x10 5 s -1

  20. Legacies of the bubble chamber

    International Nuclear Information System (INIS)

    Mulvey, J.H.

    1994-01-01

    Legacies are what we pass on to those who follow us, the foundations on which the next advances in our science are being made; the things by which we shall be remembered, recorded in learned journals, written in the text books -food for the historians of science. This is not a summary, and it will draw no conclusions. It is a personal view which will look a little wider than the main physics results to include a mention of one or two of the technologies and methods handed on to both particle physics and other branches of sciences, a brief reference to bubble chamber pictures as aids in teaching, and a comment on the challenge now increasingly applied in the UK - and perhaps elsewhere -as a criterion for funding research: will it contribute to ''wealth creation''? (orig.)

  1. Picture chamber for radiographic system

    International Nuclear Information System (INIS)

    1977-01-01

    The picture chamber for a radiographic system is characterised by a base, a first electrode carried in the base, an X-ray irradiation window provided with an outer plate and an inner plate and a conducting surface which serves as a second electrode, which has a plate gripping it at each adjacent edge and which has at the sides a space which is occupied by a filling material, maintained at a steady pressure, by means of the mounting against the base and wherein the inner plate lies against the first electrode and which is provided with a split, and with means for the separation of the split in the area of the inner plate so that a fluid may be retained in the split. (G.C.)

  2. Drift chamber data readout system

    International Nuclear Information System (INIS)

    Basiladze, S.G.; Lokhonyai, L.

    1980-01-01

    An electronic system for processing drift chamber signals is described. The system consists of 4-channel fast amplifier-discriminators of low threshold, 16-channel time-expanders transforming 0.5 μs time intervals to 10 μs and a 9-bit time-to-digital converter (TDC) recording up to 16 expanded time intervals. If the average track multiplicity is small, TDC is capable to process signals from 4 time-expanders (i.e., 64 drift gaps). In order to record multiple tracks per drift gap discriminator outputs can be connected to a number of time-expander channels. The fast clear input enables the system to be cleared within 0.5 μs. Efficient readout from TDC is facilated by reading only those channels which contain non-zero data (9 bits - drift time; 6 bits - wire number)

  3. The CAST Time Projection Chamber

    CERN Document Server

    Autiero, D.; Carmona, J.M.; Cebrian, S.; Chesi, E.; Davenport, M.; Delattre, M.; Di Lella, L.; Formenti, F.; Irastorza, I.G.; Gomez, H.; Hasinoff, M.; Lakic, B.; Luzon, G.; Morales, J.; Musa, L.; Ortiz, A.; Placci, A.; Rodriguez, A.; Ruz, J.; Villar, J.A.; Zioutas, K.

    2007-01-01

    One of the three X-ray detectors of the CAST experiment searching for solar axions is a Time Projection Chamber (TPC) with a multi-wire proportional counter (MWPC) as a readout structure. Its design has been optimized to provide high sensitivity to the detection of the low intensity X-ray signal expected in the CAST experiment. A low hardware threshold of 0.8 keV is safely set during normal data taking periods, and the overall efficiency for the detection of photons coming from conversion of solar axions is 62 %. Shielding has been installed around the detector, lowering the background level to 4.10 x 10^-5 counts/cm^2/s/keV between 1 and 10 keV. During phase I of the CAST experiment the TPC has provided robust and stable operation, thus contributing with a competitive result to the overall CAST limit on axion-photon coupling and mass.

  4. Track photographing in 8-m streamer chamber

    International Nuclear Information System (INIS)

    Anisimova, N.Z.; Davidenko, V.A.; Kantserov, V.A.; Rybakov, V.G.; Somov, S.V.

    1981-01-01

    A system for obtaining data from a streamer chamber intended for measuring muon polarization is described. An optical scheme for photographing of tracks in the chamber is given. The photographing process is complicated at the expense of large dimensions and module structure of the chamber as well as due to insufficient for direct photographing brightness of streamers. The system described was tested during a long time in a physical experiment. More than 100 thousand photos have been taken by its means [ru

  5. Drift chamber tracking with neural networks

    International Nuclear Information System (INIS)

    Lindsey, C.S.; Denby, B.; Haggerty, H.

    1992-10-01

    We discuss drift chamber tracking with a commercial log VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed

  6. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    To minimize eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical stength, it was corrugated in a hydro-forming process. The chamber is curved, to follow the beam's orbital path. Under vacuum, the chamber tends to staighten, the ceramic spacer along half of its length keeps it in place (see also 7402458).

  7. Device for gamma-chamber transducer alignment

    International Nuclear Information System (INIS)

    Mirkhodzhaev, A.Kh.; Kuznetsov, N.K.; Ostryj, Yu.E.

    1987-01-01

    The device consists of the upper part of the gamma chamber pilar to which a rod is rigidly fastened with a disk of acrylic plastic moving freely on the opposite end. The disk is placed coaxially and is equal to the gamma chamber detector crystal. The device makes it possible to use ordinary medical couches covered with a porolone mattress when the gamma chamber detector is placed below

  8. Bubble chamber: Omega production and decay

    CERN Document Server

    1973-01-01

    This image is taken from one of CERN's bubble chambers and shows the decay of a positive kaon in flight. The decay products of this kaon can be seen spiraling in the magnetic field of the chamber. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that has been heated to boiling point.

  9. MICAP, Ionization Chamber Detector Response by Monte-Carlo

    International Nuclear Information System (INIS)

    2002-01-01

    1 - Description of program or function: MICAP has been developed to determine the response of a gas-filled cavity ionization chamber or other detector type (plastic scintillator, calorimeter) in a mixed neutron and photon radiation environment. In particular, MICAP determines the neutron, photon, and total response of the detector system. The applicability of MICAP encompasses all aspects of mixed field dosimetry analysis including detector design, pre-experimental planning and post-experimental analysis. MICAP is a modular code system developed to be general with respect to problem applicability The transport modules utilize combinatorial geometry to accurately model the source/detector geometry and also use continuous energy and angle cross section and material data to represent the materials for a particular problem. 2 - Method of solution: The calculational scheme used in MICAP follows individual radiation particles incident on the detector wall material. The incident neutrons produce photons and heavy charged particles, and both primary and secondary photons produce electrons and positrons. As these charged particles enter or are produced in the detector material, they lose energy and produce ion pairs until their energy is completely dissipated or until they escape the detector. Ion recombination effects are included along the path of each charged particle rather than applied as an integral correction to the final result. The neutron response is determined from the energy deposition resulting from the transport of the charged particles and recoil heavy ions produced via the neutron interactions with the detector materials. The photon response is determined from the transport of both the primary photon radiation incident on the detector and also the secondary photons produced via the neutron interactions. MICAP not only yields the energy deposition by particle type and total energy deposited, but also the particular type of reaction, i.e. elastic scattering

  10. The Mark II Vertex Drift Chamber

    International Nuclear Information System (INIS)

    Alexander, J.P.; Baggs, R.; Fujino, D.

    1989-03-01

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 μm spatial resolution and 2 gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO 2 mixtures are presented. 10 refs., 12 figs., 1 tab

  11. Investigation of very long jet chambers

    Energy Technology Data Exchange (ETDEWEB)

    Burckhart, H J; Va' vra, J; Zankel, K; Dudziak, U; Schaile, D; Schaile, O; Igo-Kemenes, P; Lennert, P

    1986-04-01

    The electrostatic properties and the performances of very long jet chambers have been investigated. Using 100 MHz FADC wave form digitisers, the tracking accuracy, the charge division and the dE/dx performance of two chambers, one with 4.5 m long tungsten wires and one with 4 m long highly resistive ''NiCoTi'' wires have been studied. The geometry of the chambers was chosen to define some of the design parameters of the jet chamber for the OPAL detector for LEP. (orig.).

  12. Investigation of very long jet chambers

    Energy Technology Data Exchange (ETDEWEB)

    Burckhart, H J; Va' vra, J; Zankel, K; Dudziak, U; Schaile, D; Schaile, O; Igo-Kemenes, P; Lennert, P

    1986-04-01

    The electrostatic properties and the performances of very long jet chambers have been investigated. Using 100 MHz FADC wave form digitisers, the tracking accuracy, the charge division and the dE/dx performance of two chambers, one with 4.5 m long tungsten wires and one with 4 m long highly resistive ''NiCoTi'' wires have been studied. The geometry of the chambers was chosen to define some of the design parameters of the jet chamber for the OPAL detector for LEP.

  13. Cylindrical ionization chamber with compressed krypton

    International Nuclear Information System (INIS)

    Kuz'minov, V.V.; Novikov, V.M.; Pomanskii, A.A.; Pritychenko, B.V.; Viyar, J.; Garcia, E.; Morales, A.; Morales, J.; Nunes-Lagos, R.; Puimedon, J.; Saens, K.; Salinas, A.; Sarsa, M.

    1993-01-01

    A cylindrical ionization chamber with a grid is used to search for double positron decay and atomic electron conversion to a positron in 78 Kr. Krypton is the working gas material of the chamber. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. The energy resolution is 2.1% for an energy of 1.84 MeV (the source of γ-quanta is 88 Y) when the chamber is filled with a mixture of Kr+0.2% H 2 under a pressure of 25 atm

  14. D0 central tracking chamber performance studies

    International Nuclear Information System (INIS)

    Pizzuto, D.

    1991-12-01

    The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an RΦ tracking resolution compatible with the limitations imposed by physical considerations, excellent 2 track resolution, and a high track reconstruction efficiency along with a good rejection power against γ → e + e - events

  15. Precision Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Performs measurements and calibration of antennas for satellites and aircraft or groundbased systems. The chamber is primarily used for optimizing antenna...

  16. Study of the replacement correction factors for ionization chamber dosimetry by Monte Carlo simulations

    Science.gov (United States)

    Wang, Lilie

    In ionization chamber radiation dosimetry, the introduction of the ion chamber into medium will unavoidably distort the radiation field near the chamber because the chamber cavity material (air) is different from the medium. A replacement correction factor, Prepl was introduced in order to correct the chamber readings to give an accurate radiation dose in the medium without the presence of the chamber. Generally it is very hard to measure the values of Prepl since they are intertwined with the chamber wall effect. In addition, the P repl values always come together with the stopping-power ratio of the two media involved. This makes the problem of determining the P repl values even more complicated. Monte Carlo simulation is an ideal method to investigate the replacement correction factors. In this study, four different methods of calculating the values of Prepl by Monte Carlo simulation are discussed. Two of the methods are designated as 'direct' methods in the sense that the evaluation of the stopping-power ratio is not necessary. The systematic uncertainties of the two direct methods are estimated to be about 0.1-0.2% which comes from the ambiguous definition of the energy cutoff Delta used in the Spencer-Attix cavity theory. The two direct methods are used to calculate the values of P repl for both plane-parallel chambers and cylindrical thimble chambers in either electron beams or photon beams. The calculation results are compared to measurements. For electron beams, good agreements are obtained. For thimble chambers in photon beams, significant discrepancies are observed between calculations and measurements. The experiments are thus investigated and the procedures are simulated by the Monte Carlo method. It is found that the interpretation of the measured data as the replacement correction factors in dosimetry protocols are not correct. In applying the calculation to the BIPM graphite chamber in a 60Co beam, the calculated values of P repl differ from those

  17. Study on the L–H transition power threshold with RF heating and lithium-wall coating on EAST

    DEFF Research Database (Denmark)

    Chen, Leifeng; Xu, G.S.; Nielsen, Anders Henry

    2016-01-01

    The power threshold for low (L) to high (H) confinement mode transition achieved by radio-frequency (RF) heating and lithium-wall coating is investigated experimentally on EAST for two sets of walls: an all carbon wall (C) and molybdenum chamber and a carbon divertor (Mo/C). For both sets of walls...... Ploss increases with neutral density near the lower X-point in EAST with the Mo/C wall, consistent with previous results in the C wall (Xu et al 2011 Nucl. Fusion 51 072001). These findings suggest that the edge neutral density, the ion ∇B drift as well as the divertor pumping capability play important...

  18. Geometric optimization of microreactor chambers to increase the homogeneity of the velocity field

    Science.gov (United States)

    Pálovics, Péter; Ender, Ferenc; Rencz, Márta

    2018-06-01

    In this work microfluidic flow-through chambers are investigated. They are filled with magnetic nanoparticle (MNP) suspension in order to facilitate enzymatic reactions. The enzyme is immobilized on the surface of the MNPs. These reactions have been found to be flow rate dependent. To overcome this issue various chamber geometries have been examined and optimized geometries have been designed and tested experimentally. The investigation is supported with dedicated CFD simulations using the open source software OpenFOAM. The paper presents the theoretical background and the results of the simulations. The simulations have been verified with measurements and these too are presented in the paper.

  19. Hall effect thruster with an AlN chamber

    International Nuclear Information System (INIS)

    Barral, S.; Jayet, Y.; Mazouffre, S.; Veron, E.; Echegut, P.; Dudeck, M.

    2005-01-01

    The plasma discharge of a Hall-effect thruster (SPT) is strongly depending of the plasma-insulated wall interactions. These interactions are mainly related to the energy deposition, potential sheath effect and electron secondary emission rate (e.s.e.). In usual SPT, the annular channel is made of BN-SiO 2 . The SPT100-ML (laboratory model will be tested with an AlN chamber in the French test facility Pivoine in the laboratoire d'Aerothermique (Orleans-France). The different parameters such as discharge current, thrust, plasma oscillations and wall temperature will studied for several operating conditions. The results will be compared with a fluid model developed in IPPT (Warsaw-Poland) taking into account electron emission from the internal and external walls and using previous experimental measurements of e.s.e. for AlN from ONERA (Toulouse-France). The surface state of AlN will be analysed before and after experiments by an Environmental Scanning Electron Microscope and by a Strength Electron Microscope. (author)

  20. Secondary magnetic field harmonics dependence on vacuum beam chamber geometry

    Directory of Open Access Journals (Sweden)

    S. Y. Shim

    2013-08-01

    Full Text Available The harmonic magnetic field properties due to eddy currents have been studied with respect to the geometry of the vacuum beam chamber. We derived a generalized formula enabling the precise prediction of any field harmonics generated by eddy currents in beam tubes with different cross-sectional geometries. Applying our model to study the properties of field harmonics in beam tubes with linear dipole magnetic field ramping clearly proved that the circular cross section tube generates only a dipole field from eddy currents. The elliptic tube showed noticeable magnitudes of sextupole and dipole fields. We demonstrate theoretically that it is feasible to suppress the generation of the sextupole field component by appropriately varying the tube wall thickness as a function of angle around the tube circumference. This result indicates that it is possible to design an elliptical-shaped beam tube that generates a dipole field component with zero magnitude of sextupole. In a rectangular-shaped beam tube, one of the selected harmonic fields can be prevented if an appropriate wall thickness ratio between the horizontal and vertical tube walls is properly chosen. Our generalized formalism can be used for optimization of arbitrarily complex-shaped beam tubes, with respect to suppression of detrimental field harmonics.

  1. In-beam test of the RPC architecture foreseen to be used for the CBM-TOF inner wall

    Science.gov (United States)

    Petriş, M.; Bartoş, D.; Petrovici, M.; Rădulescu, L.; Simion, V.; Deppner, I.; Herrmann, N.; Simon, C.; Frühauf, J.; Kiš, M.; Loizeau, P.-A.

    2018-05-01

    The Time Of Flight (TOF) subsystem is one of the main detectors of the CBM experiment. The TOF wall in conjunction with Silicon Tracking System (STS) is foreseen to identify charged hadrons, i.e. pions, kaons and protons, with a full azimuthal coverage at 2.50 - 250 polar angles. A system time resolution of at least 80 ps, including all contributions, such as electronics jitter and the resolution of the time reference system, is required. Such a performance should be maintained up to a counting rate larger than 30 kHz/cm2 at the most inner region of TOF wall. Our R&D activity has been focused on the development of two-dimensional position sensitive Multi-gap Resistive Plate Counter (MRPC) prototypes for the forward region of the CBM-TOF subdetector, the most demanding zone in terms of granularity and counting rate. The in-beam tests using secondary particles produced in 30 GeV/u Pb ion collisions on a Pb target at SPS - CERN aimed to test the performance of these prototypes in conditions similar to the ones expected at SIS100 at FAIR. The performance of the prototypes is studied in conditions of exposure of the whole active area of the chamber to high multiplicity of reaction products. The results show that this type of MRPC fulfill the challenging requirements of the CBM-TOF wall. Therefore, such an architecture is recommended as basic solution for CBM-TOF inner zone.

  2. Polymerase chain reaction system using magnetic beads for analyzing a sample that includes nucleic acid

    Science.gov (United States)

    Nasarabadi, Shanavaz [Livermore, CA

    2011-01-11

    A polymerase chain reaction system for analyzing a sample containing nucleic acid includes providing magnetic beads; providing a flow channel having a polymerase chain reaction chamber, a pre polymerase chain reaction magnet position adjacent the polymerase chain reaction chamber, and a post pre polymerase magnet position adjacent the polymerase chain reaction chamber. The nucleic acid is bound to the magnetic beads. The magnetic beads with the nucleic acid flow to the pre polymerase chain reaction magnet position in the flow channel. The magnetic beads and the nucleic acid are washed with ethanol. The nucleic acid in the polymerase chain reaction chamber is amplified. The magnetic beads and the nucleic acid are separated into a waste stream containing the magnetic beads and a post polymerase chain reaction mix containing the nucleic acid. The reaction mix containing the nucleic acid flows to an analysis unit in the channel for analysis.

  3. Tasks related to increase of RA reactor exploitation and experimental potential, 01. Designing the protection chamber in the RA reactor hall for handling the radioactive experimental equipment (I-II) Part II, Vol. II; Radovi na povecanju eksploatacionih i eksperimentalnih mogucnosti reaktora RA, 01. Projektovanje zastitne komore u hali reaktora RA za rad sa aktivnim eksperimentalnim uredjajima (I-II), II Deo, Album II

    Energy Technology Data Exchange (ETDEWEB)

    Pavicevic, M [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1963-07-15

    This second volume of the project for construction of the protection chamber in the RA reactor hall for handling the radioactive devices includes the technical description of the chamber, calculation of the shielding wall thickness, bottom lead plate, horizontal stability of the chamber, cost estimation, and the engineering drawings.

  4. Characteristics Air Flow in Room Chamber Test Refrigerator Household Energy Consumption with Inlet Flow Variation

    Science.gov (United States)

    Susanto, Edy; Idrus Alhamid, M.; Nasruddin; Budihardjo

    2018-03-01

    Room Chamber is the most important in making a good Testing Laboratory. In this study, the 2-D modeling conducted to assess the effect placed the inlet on designing a test chamber room energy consumption of household refrigerators. Where the geometry room chamber is rectangular and approaching the enclosure conditions. Inlet varied over the side parallel to the outlet and compared to the inlet where the bottom is made. The purpose of this study was to determine and define the characteristics of the airflow in the room chamber using CFD simulation. CFD method is used to obtain flow characteristics in detail, in the form of vector flow velocity and temperature distribution inside the chamber room. The result found that the position of the inlet parallel to the outlet causes air flow cannot move freely to the side of the floor, even flow of air moves up toward the outlet. While by making the inlet is below, the air can move freely from the bottom up to the side of the chamber room wall as well as to help uniform flow.

  5. Design, construction, prototype tests and performance of a vertex chamber for the MAC detector

    International Nuclear Information System (INIS)

    Ash, W.W.; Band, H.R.; Bloom, E.D.; Bosman, M.; Camporesi, T.; Chadwick, G.B.; Delfino, M.C.; De Sangro, R.; Ford, W.T.; Gettner, M.W.; Goderre, G.P.; Godfrey, G.L.; Groom, D.E.; Hurst, R.B.; Johnson, J.R.; Lau, K.H.; Lavine, T.L.; Leedy, R.E.; Lippi, I.; Maruyama, T.; Messner, R.L.; Moromisato, J.H.; Moss, L.J.; Muller, F.; Nelson, H.N.; Peruzzi, I.; Piccolo, M.; Prepost, R.; Pyrlik, J.; Qi, N.; Read, A.L. Jr.; Ritson, D.M.; Rosenberg, L.J.; Shambroom, W.D.; Sleeman, J.C.; Smith, J.G.; Venuti, J.P.; Verdini, P.G.; Goeler, E. von; Wald, H.B.; Weinstein, R.; Wiser, D.E.; Zdarko, R.W.; Istituto Nazionale di Fisica Nucleare, Frascati; Houston Univ., TX; Northeastern Univ., Boston, MA; Stanford Univ., CA; Stanford Linear Accelerator Center, CA; Utah Univ., Salt Lake City; Wisconsin Univ., Madison

    1987-01-01

    The design considerations, construction techniques, prototype tests and performance characteristics of a pressurized drift chamber used in the MAC detector at PEP are described. The chamber consists of 324 aluminized mylar tubes of 6.9 mm diameter with wall thickness of 100 μm. With appropriate shielding it operates successfully at 4.6 cm from the beam line. It was simple to construct and was configured to permit any malfunctioning tubes to be remotely disconnected without affecting operation. The chamber operated without problems for two years in the PEP environmental with a gas mixture of 49.5% argon, 49.5% CO 2 , 1% CH 4 , at 4 atm absolute pressure. The mean spatial resolution averaged over all tubes was 45 μm. The time to distance relation for this gas mixture, along with the geometric positioning of individual wires relative to the central tracking chamber, was obtained with data from Bhabha scattering events. We also describe resolution studies performed with a prototype chamber in a SLAC test beam. A wide range of gases, gas pressures, and electronic parameters were explored. These studies proved that resolutions in the 10-50 μm range were possible. Our experience demonstrates that chambers of this type provide high precision tracking and are particularly suited for operation in regions with difficult physical access and/or high ambient radiation levels. (orig.)

  6. Design, construction, prototype tests and performance of a vertex chamber for the MAC detector

    Science.gov (United States)

    Ash, W. W.; Band, H. R.; Bloom, E. D.; Bosman, M.; Camporesi, T.; Chadwick, G. B.; Delfino, M. C.; De Sangro, R.; Ford, W. T.; Gettner, M. W.; Goderre, G. P.; Godfrey, G. L.; Groom, D. E.; Hurst, R. B.; Johnson, J. R.; Lau, K. H.; Lavine, T. L.; Leedy, R. E.; Lippi, I.; Maruyama, T.; Messner, R. L.; Moromisato, J. H.; Moss, L. J.; Muller, F.; Nelson, H. N.; Peruzzi, I.; Piccolo, M.; Prepost, R.; Pyrlik, J.; Qi, N.; Read, A. L.; Ritson, D. M.; Rosenberg, L. J.; Shambroom, W. D.; Sleeman, J. C.; Smith, J. G.; Venuti, J. P.; Verdini, P. G.; Von Goeler, E.; Wald, H. B.; Weinstein, R.; Wiser, D. E.; Zdarko, R. W.

    1987-11-01

    The design considerations, construction techniques, prototype tests and performance characteristics of a pressurized drift chamber used in the MAC detector at PEP are described. The chamber consists of 324 aluminized mylar tubes of 6.9 mm diameter with wall thickness of 100 μm. With appropriate shielding it operates successfully at 4.6 cm from the beam line. It was simple to construct and was configured to permit any malfunctioning tubes to be remotely disconnected without affecting operation. The chamber operated without problems for two years in the PEP environment with a gas mixture of 49.5% argon, 49.5% CO 2, 1% CH 4, at 4 atm absolute pressure. The mean spatial resolution averaged over all tubes was 45 μm. The time to distance relation for this gas mixture, along with the geometric positioning of individual wires relative to the central tracking chamber, was obtained with data from Bhabha scattering events. We also describe resolution studies performed with a prototype chamber in a SLAC test beam. A wide range of gases, gas pressures, and electronic parameters were explored. These studies proved that resolutions in the 10-50 μm range were possible. Our experience demonstrates that chambers of this type provide high precision tracking and are particularly suited for operation in regions with difficult physical access and/or high ambient radiation levels.

  7. The dorsal shell wall structure of Mesozoic ammonoids

    Directory of Open Access Journals (Sweden)

    Gregor Radtke

    2017-03-01

    Full Text Available The study of pristine preserved shells of Mesozoic Ammonoidea shows different types of construction and formation of the dorsal shell wall. We observe three major types: (i The vast majority of Ammonoidea, usually planispirally coiled, has a prismatic reduced dorsal shell wall which consists of an outer organic component (e.g., wrinkle layer, which is the first layer to be formed, and the subsequently formed dorsal inner prismatic layer. The dorsal mantle tissue suppresses the formation of the outer prismatic layer and nacreous layer. With the exception of the outer organic component, secretion of a shell wall is omitted at the aperture. A prismatic reduced dorsal shell wall is always secreted immediately after the hatching during early teleoconch formation. Due to its broad distribution in (planispiral Ammonoidea, the prismatic reduced dorsal shell wall is probably the general state. (ii Some planispirally coiled Ammonoidea have a nacreous reduced dorsal shell wall which consists of three mineralized layers: two prismatic layers (primary and secondary dorsal inner prismatic layer and an enclosed nacreous layer (secondary dorsal nacreous layer. The dorsal shell wall is omitted at the aperture and was secreted in the rear living chamber. Its layers are a continuation of an umbilical shell doubling (reinforcement by additional shell layers that extends towards the ventral crest of the preceding whorl. The nacreous reduced dorsal shell wall is formed in the process of ontogeny following a prismatic reduced dorsal shell wall. (iii Heteromorph and some planispirally coiled taxa secrete a complete dorsal shell wall which forms a continuation of the ventral and lateral shell layers. It is formed during ontogeny following a prismatic reduced dorsal shell wall or a priori. The construction is identical with the ventral and lateral shell wall, including a dorsal nacreous layer. The wide distribution of the ability to form dorsal nacre indicates that it is

  8. Raymond J. Chambers--A Personal Reflection

    Science.gov (United States)

    Gaffikin, Michael

    2012-01-01

    This paper is presented as a tribute to Raymond J. Chambers. As its title suggests, it is a personal reflection through the eyes of someone who worked closely with him over a period of 10 years during a latter part of his career, and who completed a doctoral thesis with aspects of the work of Chambers as its subject. During this time, author…

  9. Investigation of a multiwire proportional chamber

    International Nuclear Information System (INIS)

    Konijn, J.

    1976-01-01

    The article discusses some aspects of a prototype multiwire proportional chamber for electron detection located at IKO in Amsterdam, i.e. voltage, counting rates, noise and gas mixture (argon, ethylene bromide). The efficiency and performance of the chamber have been investigated and an error analysis is given

  10. Dual-chamber inflatable oil boom

    International Nuclear Information System (INIS)

    Blair, R.M.; Tedeschi, E.T.

    1993-01-01

    An elongated floating material containment boom section is described having a normally vertical ballasted skirt depending from flotation means, and convertible from a flattened collapsed condition to a deployable condition wherein buoyancy chamber means extending along the upper edge of said skirt are inflated to expanded buoyant configuration, including: a gas-impervious sleeve extending along the upper edge of said normally vertical skirt forming a first outer collapsible and inflatable flotation chamber, a first inflation valve connecting the interior of said sleeve with the ambient atmosphere, through which gas under pressure may be introduced into said sleeve to inflate said first buoyant outer flotation chamber, elongated gas-impervious tube means positioned inside said outer flotation chamber and forming second collapsible and inflatable internal flotation bladder chamber means, second inflation valve means connecting the interior of said bladder means through said outer flotation chamber to the ambient atmosphere through which gas under pressure may be introduced into said bladder means to inflate it forming said second flotation chamber means inside said outer flotation chamber

  11. An ionization chamber with magnetic levitated electrodes

    CERN Document Server

    Kawaguchi, T

    1999-01-01

    A new type of ionization chamber which has magnetically levitated electrodes has been developed. The electrodes are supplied voltages for the repelling of ions by a battery which is also levitated with the electrodes. The characteristics of this ionization chamber are investigated in this paper.

  12. HVAC&R Equipment Environmental Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — Description:Large "Truck" ChamberThe large "truck" chamber provides controlled air conditions from -7 °C (20 °F) to 65 °C (150 °F).Air-Conditioner and Heat Pump Test...

  13. USE OF GROWTH CHAMBERS FOR CABBAGE BREEDING

    Directory of Open Access Journals (Sweden)

    L. L. Bondareva

    2014-01-01

    Full Text Available Use of the growth chambers for cabbage breeding allows the reducing of certain stages of the breeding process and the growing biennial varieties of cabbage in a one-year cycle. In these growth chambers, the nutritional conditions, temperature, and lighting of plants are under control; the open pollination is eliminated.

  14. OPAL jet chamber full-scale prototype

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, H M; Hauschild, M; Hartmann, H; Hegerath, A; Boerner, H; Burckhart, H J; Dittmar, M; Hammarstroem, R; Heuer, R D; Mazzone, L

    1986-12-01

    The concept of a jet chamber for the central detector of OPAL was tested with a full scale prototype. The design of this prototype, its mechanical and electrical structure and its support system for high voltage, gas, laser calibration, and readout are described. Operating experience was gathered since summer 1984. The chamber performance in terms of spatial resolution and particle identification capability is given.

  15. 21 CFR 866.2120 - Anaerobic chamber.

    Science.gov (United States)

    2010-04-01

    ... and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a device intended for medical purposes to maintain an anaerobic (oxygen...

  16. Triangular tube proportional wire chamber system

    Energy Technology Data Exchange (ETDEWEB)

    Badtke, D H; Bakken, J A; Barnett, B A; Blumenfeld, B J; Chien, C Y; Madansky, L; Matthews, J A.J.; Pevsner, A; Spangler, W J [Johns Hopkins Univ., Baltimore, MD (USA); Lee, K L [California Univ., Berkeley (USA). Lawrence Berkeley Lab.

    1981-10-15

    We report on the characteristics of the proportional tube chamber system which has been constructed for muon identification in the PEP-4 experiment at SLAC. The mechanical and electrical properties of the extruded aluminum triangular tubes allow these detectors to be used as crude drift chambers.

  17. Neutron induced current pulses in fission chambers

    International Nuclear Information System (INIS)

    Taboas, A.L.; Buck, W.L.

    1978-01-01

    The mechanism of neutron induced current pulse generation in fission chambers is discussed. By application of the calculated detector transfer function to proposed detector current pulse shapes, and by comparison with actually observed detector output voltage pulses, a credible, semi-empirical, trapezoidal pulse shape of chamber current is obtained

  18. Shielding Effectiveness Measurements using a Reverberation Chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes; Bergsma, J.G.; Bergsma, Hans; van Etten, Wim

    2006-01-01

    Shielding effectiveness measurements have been performed using a reverberation chamber. The reverberation chamber methodology as we1l as the measurement setup is described and some results are given. Samples include glass reinforced plastic panels, aluminum panels with many holes, wire mesh, among

  19. The CAST time projection chamber

    International Nuclear Information System (INIS)

    Autiero, D; Beltran, B; Carmona, J M; Cebrian, S; Chesi, E; Davenport, M; Delattre, M; Di Lella, L; Formenti, F; Irastorza, I G; Gomez, H; Hasinoff, M; Lakic, B; Luzon, G; Morales, J; Musa, L; Ortiz, A; Placci, A; Rodrigurez, A; Ruz, J; Villar, J A; Zioutas, K

    2007-01-01

    One of the three x-ray detectors of the CERN Axion Solar Telescope (CAST) experiment searching for solar axions is a time projection chamber (TPC) with a multi-wire proportional counter (MWPC) as a readout structure. Its design has been optimized to provide high sensitivity to the detection of the low intensity x-ray signal expected in the CAST experiment. A low hardware threshold of 0.8 keV is set to a safe level during normal data taking periods, and the overall efficiency for the detection of photons coming from conversion of solar axions is 62%. Shielding has been installed around the detector, lowering the background level to 4.10 x 10 -5 counts cm -2 s -1 keV -1 between 1 and 10 keV. During phase I of the CAST experiment the TPC has provided robust and stable operation, thus contributing with a competitive result to the overall CAST limit on axion-photon coupling and mass

  20. Multispecimen dual-beam irradiation damage chamber

    International Nuclear Information System (INIS)

    Packan, N.H.; Buhl, R.A.

    1980-06-01

    An irradiation damage chamber that can be used to rapidly simulate fast neutron damage in fission or fusion materials has been designed and constructed. The chamber operates in conjunction with dual Van de Graaff accelerators at ORNL to simulate a wide range of irradiation conditions, including pulsed irradiation. Up to six experiments, each with up to nine 3-mm disk specimens, can be loaded into the ultrahigh vacuum chamber. Specimen holders are heated with individual electron guns, and the temperature of each specimen can be monitored during bombardment by an infrared pyrometer. Three different dose levels may be obtained during any single bombardment, and the heavy-ion flux on each of the nine specimens can be measured independently with only a brief interruption of the beam. The chamber has been in service for nearly three years, during which time approximately 250 bombardments have been successfully carried out. An appendix contains detailed procedures for operating the chamber