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Sample records for arc cryostats final

  1. Current Lead System of the SuperKEKB Final Focus SC Magnet Cryostats

    NASA Astrophysics Data System (ADS)

    Zong, Z. G.; Ohuchi, N.; Tsuchiya, K.; Arimoto, Y.; Higashi, N.; Yamaoka, H.; Kondou, Y.; Kawai, M.

    To energize the SuperKEKB final focus superconducting (SC) magnets, 110 current leads in total will be equipped in the two service cryostats. For the SC quadrupoles and solenoids, 22 leads are the conventional vapor cooled type and the others for the SC correction coils employ an HTS section at the cold ends. The qualification program on the leads is being carried out at KEK as the cryogenic acceptance test prior to installation. This paper presents the thermal and electrical results of the cryogenic tests.

  2. Final Design and Experimental Validation of the Thermal Performance of the LHC Lattice Cryostats

    NASA Astrophysics Data System (ADS)

    Bourcey, N.; Capatina, O.; Parma, V.; Poncet, A.; Rohmig, P.; Serio, L.; Skoczen, B.; Tock, J.-P.; Williams, L. R.

    2004-06-01

    The recent commissioning and operation of the LHC String 2 have given a first experimental validation of the global thermal performance of the LHC lattice cryostat at nominal cryogenic conditions. The cryostat designed to minimize the heat inleak from ambient temperature, houses under vacuum and thermally protects the cold mass, which contains the LHC twin-aperture superconducting magnets operating at 1.9 K in superfluid helium. Mechanical components linking the cold mass to the vacuum vessel, such as support posts and insulation vacuum barriers are designed with efficient thermalisations for heat interception to minimise heat conduction. Heat inleak by radiation is reduced by employing multilayer insulation (MLI) wrapped around the cold mass and around an aluminium thermal shield cooled to about 60 K. Measurements of the total helium vaporization rate in String 2 gives, after substraction of supplementary heat loads and end effects, an estimate of the total thermal load to a standard LHC cell (107 m) including two Short Straight Sections and six dipole cryomagnets. Temperature sensors installed at critical locations provide a temperature mapping which allows validation of the calculated and estimated thermal performance of the cryostat components, including efficiency of the heat interceptions.

  3. Final Technical Report on STTR Project DE-FG02-04ER86191 Hydrogen Cryostat for Muon Beam Cooling

    SciTech Connect

    Johnson, Rolland P.

    2008-05-07

    The project was to develop cryostat designs that could be used for muon beam cooling channels where hydrogen would circulate through refrigerators and the beam-cooling channel to simultaneously refrigerate 1) high-temperature-superconductor (HTS) magnet coils, 2) cold copper RF cavities, and 3) the hydrogen that is heated by the muon beam. In an application where a large amount of hydrogen is naturally present because it is the optimum ionization cooling material, it was reasonable to explore its use with HTS magnets and cold, but not superconducting, RF cavities. In this project we developed computer programs for simulations and analysis and conducted experimental programs to examine the parameters and technological limitations of the materials and designs of Helical Cooling Channel (HCC) components (magnet conductor, RF cavities, absorber windows, heat transport, energy absorber, and refrigerant).The project showed that although a hydrogen cryostat is not the optimum solution for muon ionization cooling channels, the studies of the cooling channel components that define the cryostat requirements led to fundamental advances. In particular, two new lines of promising development were opened up, regarding very high field HTS magnets and the HS concept, that have led to new proposals and funded projects.

  4. Cryostat and CCD for MEGARA at GTC

    NASA Astrophysics Data System (ADS)

    Castillo-Domínguez, E.; Ferrusca, D.; Tulloch, S.; Velázquez, M.; Carrasco, E.; Gallego, J.; Gil de Paz, A.; Sánchez, F. M.; Vílchez Medina, J. M.

    2012-09-01

    MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the new integral field unit (IFU) and multi-object spectrograph (MOS) instrument for the GTC. The spectrograph subsystems include the pseudo-slit, the shutter, the collimator with a focusing mechanism, pupil elements on a volume phase holographic grating (VPH) wheel and the camera joined to the cryostat through the last lens, with a CCD detector inside. In this paper we describe the full preliminary design of the cryostat which will harbor the CCD detector for the spectrograph. The selected cryogenic device is an LN2 open-cycle cryostat which has been designed by the "Astronomical Instrumentation Lab for Millimeter Wavelengths" at INAOE. A complete description of the cryostat main body and CCD head is presented as well as all the vacuum and temperature sub-systems to operate it. The CCD is surrounded by a radiation shield to improve its performance and is placed in a custom made mechanical mounting which will allow physical adjustments for alignment with the spectrograph camera. The 4k x 4k pixel CCD231 is our selection for the cryogenically cooled detector of MEGARA. The characteristics of this CCD, the internal cryostat cabling and CCD controller hardware are discussed. Finally, static structural finite element modeling and thermal analysis results are shown to validate the cryostat model.

  5. Specification for the Reattachment of the EC North Cryostat Heads

    SciTech Connect

    Luther, R.; /Fermilab

    1991-03-20

    This Engineering Note defines technical requirements and the scope of work for reattachment of the heads of the North EC cryostat This work is to be done in the D-Zero. Assembly Building (DAB) at Fermilab and is expected to begin around May 15, 1991. The task consists primarily of welding four heads onto a 17-foot diameter stainless steel double-wall pressure/varuum vessel. Nominal thicknesses of the welds are all 5/8-inch. Root passes are to be made by TIG welding and the balance by MIG welding. No radiography is required; other NDE per ASME Code, Section VIII, Div. 1. All work is to be done in accordance with the Rules of the National Board of Boiler and Pressure Vessel Inspectors (ANSI/NB-23), and repairs to the inner vessel are to be documented by the R-1 form exeruted by the Contractorts Authorized Inspector. The Contractor will be expected to work two shifts per day, five days per week to support the Fermilab schedule. Details of the cryostat are given on Fermi1ab Drawings 3740.220-ME-222256, Rev. R, 3740.224-ME-273071, and 3740.224-ME-273039. The cryostat was fabricated by Process Engineering, Inc. ofPlaistow, NH in 1989-90. The heads were removed using hand-held air-arc gouging equipment. As a result the welding grooves are not straight and their widths are not uniform, In some places the width may be as wide as 1-inch. For the purposes of quotation, the Contractor should assume a uniform weld groove as shown in Figure 1. The amount of weld metal to be deposited for this geometry is estimated to be 500 lbs. Upon completion, the final contract price will be determined by the following formula: Final Price = Contract Price x (lbs of weld metal deposited/500). Methods of determining the amount ofweld metal deposited will be agreed upon before award of the contract.

  6. CRYOSTAT (18-IML-1)

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The CRYOSTAT is an autonomously working rack mounted equipment. It provides two thermostat chambers, independently controlled by a processor via on/off switching of the current through peltier elements. The temperature profiles of the freezer and stabilizer are subdivided in a common number of steps, each one with a preprogrammable temperature gradient or at constant temperature. Core parameters can be reprogrammed by crew interaction in case of rescheduling the CRYOSTAT operation time due to changed mission requirements or contingency. Actions of the CRYOSTAT (e.g., opening the slide), the steps, actual temperature of the thermostat chambers, experiment time, and the housekeeping data are recorded on a built-in RAM and a tape. In each thermostat chamber, a specific sample container can be inserted which consists of a transparent Plexiglas block accommodating seven crystallization experiments.

  7. Vibration measurement in the KAGRA cryostat

    NASA Astrophysics Data System (ADS)

    Chen, D.; Naticchioni, L.; Khalaidovski, A.; Yamamoto, K.; Majorana, E.; Sakakibara, Y.; Tokoku, C.; Suzuki, T.; Kimura, N.; Koike, S.; Uchiyama, T.; Kawamura, S.

    2014-11-01

    The Japanese gravitational wave observatory KAGRA will be operated at cryogenic temperatures to reduce thermal noise. Four main mirrors and their suspension systems, called cryogenic payloads, will be cooled in the cryostat. Vibrations of the cryostat and the cryocooler can contaminate the output of the detector. One of the noise paths is the heat link made from the pure soft metal between the cryogenic payload and cryocoolers to cool the payload. In order to evaluate this noise amplitude, we measured the vibration of the radiation shield at cryogenic temperatures at the cryostat production site in Yokohama, Japan. For this measurement, we developed cryogenic accelerometers. Based on the result of this measurement, we calculated the noise in the KAGRA interferometer. Our results show that with the current design, the seismic noise goal formulated for KAGRA cannot be achieved. Finally, we present a possible design optimization that is meant to reach the nominal sensitivity of the detector.

  8. Small Business Innovations (Cryostat)

    NASA Technical Reports Server (NTRS)

    1991-01-01

    General Pneumatics Corporation, Scottsdale, AZ, developed an anti- clogging cryostat that liquifies gases by expansion for high pressure through a nozzle to produce cryorefrigeration based on their Kennedy Space Center Small Business Innovation Research (SBIR) work to develop a Joule-Thomson (JT) expansion valve that is less susceptible to clogging by particles or condensed contaminants in the flow than a non-contaminating compressor in a closed cycle Linde-Hampson cryocooler used to generate cryogenic cooling for infrared sensors, super conductors, supercooled electronics and cryosurgery.

  9. Implementation of Submerged Arc Welding Training. Final Report.

    ERIC Educational Resources Information Center

    Bowick, Earl; Todd, John

    A unit on submerged arc welding (SAW) was developed and integrated into the welding program at Seattle Central Community College (Washington) during the period December 1983 through May 1984. During this time, 10 major users of SAW in the area were contacted and mailed questionnaires. Follow up consisted of telephone calls and personal contact as…

  10. The low-cost cryostat

    NASA Technical Reports Server (NTRS)

    Bronson, J. C.

    1970-01-01

    Inexpensive method of fabricating cryostats uses polyurethane, super insulation, fiber glass, and cardboard/plywood. Cryostat weighs 1/10 of Dewar, occupies about same volume, is easy to handle, requires no metal parts, and can be formed into virtually any configuration.

  11. Platelet-cooled plasma arc torch. Final report

    SciTech Connect

    1995-10-01

    In this 12-month program sponsored by the DOE Morgantown Energy Technology Center, Aerojet designed, fabricated, and tested six platelet cooled electrodes for a Retech 75T (90 MW) plasma arc torch capable of processing mixed radioactive waste. Two of the electrodes with gas injection through the electrode wall demonstrated between eight and forty times the life of conventional water cooled electrodes. If a similar life increase can be produced in a 1 Mw size electrode, then electrodes possessing thousands, rather than hundreds, of hours of life will be available to DOE for potential application to mixed radioactive waste processing.

  12. Specification for the Reattachment of the EC South Cryostat Heads

    SciTech Connect

    Luther, R.; /Fermilab

    1991-08-01

    This Engineering Note defines technical requirements and the scope of work for reattachment of the heads of the South EC cryostat. This work is to be done in the clean room at the D-Zero Assembly Building (DAB) at Fermilab.and is expected to begin around September 15, 1991. The task consists primarily of welding four heads onto a 17-foot diameter stainless steel double-wall pressure/vacuum vessel. Nominal thicknesses of the welds are all 5/8-inch. Root passes are to be made by TIG welding and the balance by MIG welding. No radiography is required; other NDE per ASME Code, Section VIII, Div. 1. All work is to be done in accordance with the Rules of the National Board of Boiler and Pressure Vessel Inspectors (ANSI/NB-23), and repairs to the inner vessel are to be documented by the R-1 form executed by the Contractor's Authorized Inspector. The Contractor will be expected to work two shifts per day, five days per week to support the Fermilab schedule. Details of the cryostat are given on Fermilab Drawings 3740.220-ME-222256, Rev. R, 3740.224-ME-273071, and 3740.224-ME-273039. The cryostat was fabricated by Process Engineering, Inc. of Plaistow, NH in 1989-90. The heads were removed using hand-held air-arc gouging equipment. As a result the welding grooves are not straight and their widths are not uniform. In some places the width maybe as wide as 1-inch. For the purposes of quotation, the Contractor should assume a uniform weld groove as shown in Figure 1. The amount of weld metal to be deposited for this geometry is estimated to be 500 lbs. Upon completion, the final contract price will be determined by the following formula: Final Price = Contract Price x (lbs of weld metal deposited/500). Methods of determining the amount of weld metal deposited will be agreed upon before award of the contract.

  13. Low cost cryostat

    NASA Technical Reports Server (NTRS)

    Stephens, J. B. (Inventor)

    1980-01-01

    A cryostat for use in a low or a substantially gravity-free environment adapted to cool an experiment through the use of helium 2, or helium in its super fluid state is characterized by a number of interchangeable daughter dewars and helium supply or mother dewar. A low pressure venting system is provided for converting helium contained in the mother dewar to a superfluid state for use as a primary cryogen. Each daughter dewar is adapted to be removably mounted in mated relation on the mother dewar and is characterized by support for an experiment package, a source of helium to be employed as a secondary cryogen. A heat pipe is suspended from each daughter dewar and adapted to be extended into the mother dewar for facilitating cooling of the secondary cryogen. A transfer of heat from the package to the primary cryogen, via the secondary cryogen, is accommodated as a film flow of helium 2 progresses from the heat pipe to the experiment dewar.

  14. MEGARA cryostat advanced design

    NASA Astrophysics Data System (ADS)

    Ferrusca, D.; Castillo-Domínguez, Edgar; Velázquez, M.; Gil de Paz, A.; Carrasco, E.; Gallego, J.; Cedazo, R.; Iglesias-Páramo, J.

    2014-08-01

    MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit and Multi-Object Spectrograph designed for the GTC (Gran Telescopio de Canarias) 10.4m telescope in La Palma. MEGARA project has already passed preliminary design review and the optics critical design review, first-light it is expected to take place at the end of 2016. MEGARA is a development under a GRANTECAN contract. In this paper we summarize the current status of the LN2 open-cycle cryostat which has been designed by the "Astronomical Instrumentation Lab for Millimeter Wavelengths" at the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) and emphasize the key parts of the system that have updated since the Preliminary Design, the main activities related to acceptance, integration, fabrication and maintenance plans which fit into the overall structure of the management plan of MEGARA are also described. The cryogenic work package of MEGARA has completed all the design stages and is ready for its Critical Design Review and then proceed to fabrication.

  15. Design of the VLPC Cryostats

    SciTech Connect

    Rucinski, Russell A.

    2001-07-19

    A short profile (40 cm), long length (2.50 m) rectangular helium cryostat has been designed, built and tested for maintaining electronic chips at a stable 9.0 Kelvin temperature. Heat load, and thermal stresses were major design considerations. The distance from room temperature to liquid nitrogen intercept temperature is only 8 centimeters. Liquid nitrogen temperature to liquid helium temperature occurs in 13 centimeters. An alloy known as Invar, 36% Nickel, balance Iron, was used to fabricate the vessel walls and liquid nitrogen heat intercept tubing because of it's low coefficient of thermal expansion. The cryostat accepts fifty-one, 3.5 cm x 42.5 cm devices that extend 26.7 cm into the cryostat. Tight clearance fits to the liquid nitrogen and liquid helium intercepts are maintained. Gaseous helium is used within the cryostat for heat transfer.

  16. Development of the Facet Cryostat

    NASA Technical Reports Server (NTRS)

    Nash, A.; Shields, P.; Jirmanus, M.

    1999-01-01

    A proof of concept prototype cryostat has been developed to demonstrate the ability to accommodate low temperature science investigations within the constraints of the Hitchhiker siderail carrier on the Space Shuttle.

  17. Cryostat with Foil and MLI

    SciTech Connect

    Hwang, Peter K.F.; Gung, Chen-yu

    2005-10-06

    Induction cores are used to accelerate heavy ion beam array, which are built around the outer diameter of the cryostat housing the superconducting quadruple array. Compact cryostat is highly desirable to reduce the cost of the induction cores. Recent experiences in fabrication of a cryostat for single beam transport revealed that it is possible to reduce the spacing in the cryostat vacuum jacket by using low-emissivity thermal insulation material instead of conventional MLI. However, it is labor-intensive to install the new type of insulation as compared with using MLI. It is promising to build a cost-effective compact cryostat for quadruple magnet array for heavy ion beam array transport by using low-emissivity material combined with conventional MLI as radiation insulation. A matrix of insulation designs and tests will be performed as the feasibility study and for the selection of the optimal thermal insulation as the Phase I work. The selected mixed insulation will be used to build prototype compact cryostats in the Phase II project, which are aiming for housing quadruple doublet array. In this STTR phase I study, a small cryostat has been designed and built to perform calorimetric characterization of the heat load in a liquid helium vessel insulated with a vacuum layer with a nominal clearance of 3.5 mm. The vacuum clearance resembled that used in the warm-bore beam tube region in a prototype cryostat previously built for the heavy ion beam transport experiment. The vacuum clearance was geometrically restricted with a heater shell with the temperature controlled at near 300 K. Various combinations of radiation and thermal shields were installed in the tight vacuum clearance for heat load measurements. The measured heat loads are reported and compared with previous test result using a compact vacuum layer. Further developments of the thermal insulations used in the present study are discussed. The compact cryostat with foil and MLI insulation may be used in the

  18. Helium pressures in RHIC vacuum cryostats and relief valve requirements from magnet cooling line failure

    SciTech Connect

    Liaw, C.J.; Than, Y.; Tuozzolo, J.

    2011-03-28

    A catastrophic failure of the RHIC magnet cooling lines, similar to the LHC superconducting bus failure incident, would pressurize the insulating vacuum in the magnet and transfer line cryostats. Insufficient relief valves on the cryostats could cause a structural failure. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the vacuum cryostat and discharging via the reliefs into the RHIC tunnel, had been developed to calculate the helium pressure inside the cryostat. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces were included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Existing relief valve sizes were reviewed to make sure that the maximum stresses, caused by the calculated maximum pressures inside the cryostats, did not exceed the allowable stresses, based on the ASME Code B31.3 and ANSYS results. The conclusions are as follows: (1) The S/F simulation results show that the highest internal pressure in the cryostats, due to the magnet line failure, is {approx}37 psig (255115 Pa); (2) Based on the simulation, the temperature on the cryostat chamber, INJ Q8-Q9, could drop to 228 K, which is lower than the material minimum design temperature allowed by the Code; (3) Based on the ASME Code and ANSYS results, the reliefs on all the cryostats inside the RHIC tunnel are adequate to protect the vacuum chambers when the magnet cooling lines fail; and (4) In addition to the pressure loading, the thermal deformations, due to the temperature decrease on the cryostat chambers, could also cause a high stress on the chamber, if not properly supported.

  19. Corrosion and arc erosion in MHD channels. Final report

    SciTech Connect

    Rosa, R.J.; Pollina, R.J. |

    1992-08-01

    The problems connected with gas side corrosion for the design of the lA4 (POC) channel hardware are explored and results of gas side wear rate tests in the Textron Mark VII facility are presented. It is shown that the proposed designs meet a 2000 hour lifetime criterion based upon these materials tests. Improvement in cathode lifetime is demonstrated with lower voltage intercathode gaps. The corrosion of these materials is discussed and it is shown how lifetimes are dependent upon gap voltage and average metal temperature. The importance of uniformity of slagging to the durability of the anode wall is demonstrated. The wear mechanism of the anodes in the MHD channel is analyzed. In addition to gas-side corrosion, the results of specific water corrosion tests of sidewall materials are discussed. All of the tests reported here were carried out to confirm the gas-side performance and the manufacturability of anode and sidewall designs and to address questions posed about the durability of tungsten-copper on the waterside. the results of water corrosion tests of the tungsten copper alloy sidewall material are presented to show that with proper control of waterside pH and, if necessary, dissolved oxygen, one can obtain reliable performance with no degradation of heat transfer with this material. The final choice of materials was determined primarily by the outcome of these tests and also by the question of the manufacturability of the prospective designs.

  20. Optical tuning in the arcs and final focus sections of the Stanford Linear Collider

    SciTech Connect

    Bambade, P.S.

    1989-03-01

    In this thesis, we present the experimental tuning procedures developed for the Arcs and for the Final Focus Section of the Stanford Linear Collider (SLC). Such tuning is necessary to maximize the luminosity, by minimizing the beam size at the interaction point, and to reduce backgrounds in the experiment. In the final Focus Section, the correction strategy must result from the principles of the optical design, which is based on cancellations between second order aberrations, and on the ability to measure micron-size beams typical of the SLC. In the Arcs, the corrections were designed after the initial commissioning, to make the system more error-tolerant, through a modification in the optical design, and to enable adjustments of the beam phase-space a the injection to the Final Focus System, through a harmonic perturbation technique inspired from circular accelerators. Although the overall optimization of the SLC is not entirely finished, an almost optimal set-up has been achieved for the optics of the Arcs and of the Final Focus Section. Beams with transverse sizes close to the nominal ones, of a few microns, have been obtained at the interaction point. We present and discuss our results and the optical limits to the present performance. 24 refs., 25 figs., 2 tabs.

  1. Safety analysis results for cryostat ingress accidents in ITER

    SciTech Connect

    Merrill, B.J.; Cadwallader, L.C.; Petti, D.A.

    1997-06-01

    Accidents involving the ingress of air, helium, or water into the cryostat of the International Thermonuclear Experimental Reactor (ITER) tokamak design have been analyzed with a modified version of the MELCOR code for the ITER Non-site Specific Safety Report (NSSR-1). The air ingress accident is the result of a postulated breach of the cryostat boundary into an adjoining room. MELCOR results for this accident demonstrate that the condensed air mass and increased heat loads are not a magnet safety concern, but that the partial vacuum in the adjoining room must be accommodated in the building design. The water ingress accident is the result of a postulated magnet arc that results in melting of a Primary Heat Transport System (PHTS) coolant pipe, discharging PHTS water and PHTS water activated corrosion products and HTO into the cryostat. MELCOR results for this accident demonstrate that the condensed water mass and increased heat loads are not a magnet safety concern, that the cryostat pressure remains below design limits, and that the corrosion product and HTO releases are well within the ITER release limits. 6 refs., 2 figs., 1 tab.

  2. Safety analysis results for cryostat ingress accidents in ITER

    SciTech Connect

    Merrill, B.J.; Cadwallader, L.C.; Petti, D.A.

    1996-12-31

    Accidents involving the ingress of air or water into the cryostat of the International Thermonuclear Experimental Reactor (ITER) tokamak design have been analyzed with a modified version of the MELCOR code for the ITER Non-site Specific Safety Report (NSSR-1). The air ingress accident is the result of a postulated breach of the cryostat boundary into an adjoining room. MELCOR results for this accident demonstrate that the condensed air mass and increased heat loads are not a magnet safety concern, but that the partial vacuum in the adjoining room must be accommodated in the building design. The water ingress accident is the result of a postulated magnet arc that results in melting of a Primary Heat Transport System (PHTS) coolant pipe, discharging PHTS water and PHTS water activated corrosion products and HTO into the cryostat. MELCOR results for this accident demonstrate that the condensed water mass and increased heat loads are not a magnet safety concern, that the cryostat pressure remains below design limits, and that the corrosion product and HTO releases are well within the ITER release limits.

  3. Safety Analysis Results for Cryostat Ingress Accidents in ITER

    NASA Astrophysics Data System (ADS)

    Merrill, B. J.; Cadwallader, L. C.; Petti, D. A.

    1997-06-01

    Accidents involving the ingress of air, helium, or water into the cryostat of the International Thermonuclear Experimental Reactor (ITER) tokamak design have been analyzed with a modified version of the MELCOR code for the ITER Non-site Specific Safety Report (NSSR-1). The air ingress accident is the result of a postulated breach of the cryostat boundary into an adjoining room. MELCOR results for this accident demonstrate that the condensed air mass and increased heat loads are not a magnet safety concern, but that the partial vacuum in the adjoining room must be accommodated in the building design. The water ingress accident is the result of a postulated magnet arc that results in melting of a Primary Heat Transport System (PHTS) coolant pipe, discharging PHTS water and PHTS water activated corrosion products and HTO into the cryostat. MELCOR results for this accident demonstrate that the condensed water mass and increased heat loads are not a magnet safety concern, that the cryostat pressure remains below design limits, and that the corrosion product and HTO releases are well within the ITER release limits.

  4. Solid oxide fuel cell processing using plasma arc spray deposition techniques. Final report

    SciTech Connect

    Ray, E.R.; Spengler, C.J.; Herman, H.

    1991-07-01

    The Westinghouse Electric Corporation, in conjunction with the Thermal Spray Laboratory of the State University of New York, Stony Brook, investigated the fabrication of a gas-tight interconnect layer on a tubular solid oxide fuel cell with plasma arc spray deposition. The principal objective was to determine the process variables for the plasma spray deposition of an interconnect with adequate electrical conductivity and other desired properties. Plasma arc spray deposition is a process where the coating material in powder form is heated to or above its melting temperature, while being accelerated by a carrier gas stream through a high power electric arc. The molten powder particles are directed at the substrate, and on impact, form a coating consisting of many layers of overlapping, thin, lenticular particles or splats. The variables investigated were gun power, spray distance, powder feed rate, plasma gas flow rates, number of gun passes, powder size distribution, injection angle of powder into the plasma plume, vacuum or atmospheric plasma spraying, and substrate heating. Typically, coatings produced by both systems showed bands of lanthanum rich material and cracking with the coating. Preheating the substrate reduced but did not eliminate internal coating cracking. A uniformly thick, dense, adherent interconnect of the desired chemistry was finally achieved with sufficient gas- tightness to allow fabrication of cells and samples for measurement of physical and electrical properties. A cell was tested successfully at 1000{degree}C for over 1,000 hours demonstrating the mechanical, electrical, and chemical stability of a plasma-arc sprayed interconnect layer.

  5. The role of continental margins in the final stages of arc formation: Constraints from teleseismic tomography of the Gibraltar and Calabrian Arc (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Argnani, Andrea; Cimini, Giovanni Battista; Frugoni, Francesco; Monna, Stephen; Montuori, Caterina

    2016-05-01

    The deep seismicity and lateral distribution of seismic velocity in the Central Western Mediterranean, point to the existence under the Alboran and Tyrrhenian Seas of two lithospheric slabs reaching the mantle transition zone. Gibraltar and Calabrian narrow arcs correspond to the slabs. Similarities in the tectonic and mantle structure of the two areas have been explained by a common subduction and roll-back mechanism, in which the two arcs are symmetrical end members. We present a new 3-D tomographic model at mantle scale for the Calabrian Arc and compare it with a recently published model for the Gibraltar Arc by Monna et al. (2013a). The two models, calculated with inversion of teleseismic phase arrivals, have a scale and parametrization that allow for a direct comparison. The inclusion in both inversions of ocean bottom seismometer broadband data improves the resolution of the areas underlying the seafloor networks. This additional information is used to resolve the deep structure and constrain the reconstruction of the Central Western Mediterranean geodynamic evolution. The Gibraltar tomography model suggests that the slab is separated from the Atlantic oceanic domain by a portion of African continental margin, whereas the Calabrian model displays a continuous oceanic slab that is connected, via a narrow passage (~ 350 km), to the Ionian basin oceanic domain. Starting from the comparison of the two models we propose the following interpretation: within the Mediterranean geodynamic regime (dominated by slab rollback) the geometry of the African continental margin, located on the lower plate, represents a critical control on the evolution of subduction. As buoyant continental lithosphere entered the subduction zones, slab pull caused tears in the subducted lithosphere. This tectonic response, which occurred in the final stages of arc evolution and was strongly controlled by the paleogeography of the subducted plates, explains the observed differences between the

  6. Analysis Supporting MSFC Cryostat Testing Unit

    NASA Technical Reports Server (NTRS)

    Foster, Winfred A., Jr.; Jenkins, Rhonald M.

    1997-01-01

    This report summarizes the results obtained from an analysis of the NASA Marshall Spaceflight Center (MSFC) cryostat testing unit. A finite element model was generated to determine both temperature distribution and stress distribution in the cryostat testing unit for load conditions supplied by MSFC. This report contains the results of that analysis.

  7. Thermal architecture of the Clover cryostats

    NASA Astrophysics Data System (ADS)

    Grainger, William F.; Ade, Peter A. R.; Hargrave, Peter; Chase, Simon; Kiernan, Brian; North, Chris E.

    2010-07-01

    We discuss the Clover cryostats, which are dry cryostats containing three stages of cooling; a pulse tube cooler, a sorption fridge and a continuous miniature dilution refrigerator. We describe the thermal architecture of the system and present thermal data for the various stages including its performance when tilted.

  8. Simple fiber optic coupled luminescence cryostat

    NASA Astrophysics Data System (ADS)

    Meyer, G. D.; Ortiz, T. P.; Costello, A. L.; Brozik, J. A.; Kenney, J. W.

    2002-12-01

    An easy to fabricate, easy to operate, miniature liquid helium insert cryostat has been designed for variable low-temperature luminescence investigations in the 2.7-77 K region with minimal liquid helium consumption. The cryostat, which can be used inside of a standard liquid helium storage Dewar, is optically coupled both to the luminescence spectrophotometer and to the chosen luminescence excitation source (laser or conventional) by a single 1 mm fused silica fiber optic cable. This extremely simple and compact optical system is designed to give highly reproducible luminescence excitation and collection efficiencies for quantitative luminescence intensity studies. Temperature control in the cryostat is achieved through the dynamic balance of up to three distinct heating/cooling processes: raising or lowering the cryostat with respect to the liquid helium level in the Dewar, heating the cryostat with a small resistance heater, or pumping on the cryostat for sub-4.2 K temperatures. The cryostat can operate effectively throughout the 2.7-77 K range in liquid helium storage Dewars containing less than a liter of liquid helium. The wide range of spectroscopic experiments that this novel optical cryostat design can support is illustrated by a temperature-dependent zero field splitting luminescence lifetime study of Ru(bpy)3Cl2, a temperature-dependent relative luminescence intensity (quantum yield) study of Ru(bpy)3Cl2, and a temperature-dependent luminescence vibronic fine structure study of Ti(Cp)2(NCS)2.

  9. Final Design And Manufacturing of the PEP II High Energy Ring Arc Bellows Module

    SciTech Connect

    Kurita, Nadine R.; Kulikov, Artem; Corlett, John; /LBL, Berkeley

    2011-09-01

    A novel RF shield bellows module developed at SLAC has been successfully manufactured and installed in the PEP-II High Energy Ring (HER). Tests indicate that the module meets its performance and operational requirements. The primary function of the bellows module is to allow for thermal expansion of the chambers and for lateral, longitudinal and angular offsets due to tolerances and alignment, while providing RF continuity between adjoining chambers. An update on the Arc bellows module for the PEP-II High Energy Ring is presented. Final design, manufacturing issues, material and coating selection, and tribological and RF testing are discussed. Performance and operational requirements are also reviewed. The RF shield design has been proven during assembly to allow for large manufacturing tolerances without reducing the mechanical spring force below required values. In addition, the RF shield maintains electrical contact even with large misalignments across the module.

  10. Cryostat for testing RF power couplers

    SciTech Connect

    Kuchnir, M.; Champion, M.S.; Koepke, K.P.; Misek, J.R.

    1996-03-01

    Similar to the power leads of accelerator superconducting magnets, the power couplers of accelerator superconducting cavities are components that link room temperature to superfluid helium temperature for the purpose of energy transfer. Instead of conducting kiloamperes of current they guide megawatts of RF power between those two temperatures. In this paper we describe a cryostat designed for testing the performance of these components and measuring their heat loads. A special feature of this cryostat is its minimum liquid inventory that considerably simplifies safety related requirements. This cryostat is part of a Fermilab facility contributing to the international collaboration working on TESLA (TeV Electron Superconducting Linear Accelerator). This facility is now operational and we will be presenting specifications as well as performance data on the cryostat as well as the first pair of power couplers tested with it.

  11. A new cryostat for precise temperature control

    NASA Astrophysics Data System (ADS)

    Dong, B.; Zhou, G.; Liu, L. Q.; Zhang, X.; Xiong, L. Y.; Li, Q.

    2013-09-01

    Gifford-McMahon (GM) cryocoolers are often used in cryostat as cold sources. It has advantages of simple structure and low operating cost as well as disadvantages of vibration and temperature oscillation, which are fatal for some applications that are very sensitive to temperature stability at low temperature. To solve the problem, a thermal analysis model which is used to simulate heat transfer in the cryostat is built and discussed. According to the analysis results, a cryostat that can provide variable temperature (4-20 K) for the accurate temperature control experiments is designed and manufactured. In this cryostat, a polytetrafluoroethylene (PTFE) sheet is used as a thermal damper to reduce the temperature oscillation, with which, the temperature oscillation of the sample cooling holder is less than 4 mK at the 20 K region.

  12. The LINC-NIRVANA IR cryostat

    NASA Astrophysics Data System (ADS)

    Laun, W.; Baumeister, H.; Bizenberger, P.

    2006-06-01

    The MPIA is leading an international consortium of institutes building an instrument called LINC-NIRVANA. The instrument will combine the light from the two 8.4 m primary mirrors of the LBT. The beam combiner will operate at wavelengths between 1.1 and 2.4 microns, using a Hawaii2 detector. A volume of about 1.6 m high with a diameter of about 0.65 m is required for the cold optics. The size of the instrument and the high requirements on vibrations brought us to a new approach for the cooling of the cryostat, which has never been tried in astronomy. The cryostat will be cooled by a flow of Helium gas. The cooler which cools the gas will be placed far away on a different level in the telescope building. The cold helium will be fed through long vacuum isolated transfer lines to the instrument cryostat. Inside the cryostat a tube will be wrapped around the mounting structure of the cold optics. The first hardware arrived at the MPIA in 2005 and the system will soon be tested in our labs.

  13. Engineering design of vertical test stand cryostat

    SciTech Connect

    Suhane, S.K.; Sharma, N.K.; Raghavendra, S.; Joshi, S.C.; Das, S.; Kush, P.K.; Sahni, V.C.; Gupta, P.D.; Sylvester, C.; Rabehl, R.; Ozelis, J.; /Fermilab

    2011-03-01

    Under Indian Institutions and Fermilab collaboration, Raja Ramanna Centre for Advanced Technology and Fermi National Accelerator Laboratory are jointly developing 2K Vertical Test Stand (VTS) cryostats for testing SCRF cavities at 2K. The VTS cryostat has been designed for a large testing aperture of 86.36 cm for testing of 325 MHz Spoke resonators, 650 MHz and 1.3 GHz multi-cell SCRF cavities for Fermilab's Project-X. Units will be installed at Fermilab and RRCAT and used to test cavities for Project-X. A VTS cryostat comprises of liquid helium (LHe) vessel with internal magnetic shield, top insert plate equipped with cavity support stand and radiation shield, liquid nitrogen (LN{sub 2}) shield and vacuum vessel with external magnetic shield. The engineering design and analysis of VTS cryostat has been carried out using ASME B&PV Code and Finite Element Analysis. Design of internal and external magnetic shields was performed to limit the magnetic field inside LHe vessel at the cavity surface <1 {micro}T. Thermal analysis for LN{sub 2} shield has been performed to check the effectiveness of LN{sub 2} cooling and for compliance with ASME piping code allowable stresses.

  14. Throttling Cryogen Boiloff To Control Cryostat Temperature

    NASA Technical Reports Server (NTRS)

    Cunningham, Thomas

    2003-01-01

    An improved design has been proposed for a cryostat of a type that maintains a desired low temperature mainly through boiloff of a liquid cryogen (e.g., liquid nitrogen) at atmospheric pressure. (A cryostat that maintains a low temperature mainly through boiloff of a cryogen at atmospheric pressure is said to be of the pour/fill Dewar-flask type because its main component is a Dewar flask, the top of which is kept open to the atmosphere so that the liquid cryogen can boil at atmospheric pressure and cryogenic liquid can be added by simply pouring it in.) The major distinguishing feature of the proposed design is control of temperature and cooling rate through control of the flow of cryogen vapor from a heat exchanger. At a cost of a modest increase in complexity, a cryostat according to the proposal would retain most of the compactness of prior, simpler pour/fill Dewar-flask cryostats, but would utilize cryogen more efficiently (intervals between cryogen refills could be longer).

  15. Cryostat design for the Superconducting Super Collider

    SciTech Connect

    Nicol, T.H.

    1990-09-01

    The cryostat of an SSC dipole magnet consists of all magnet components except the cold mass assembly. It serves to support the cold mass accurately and reliably within the vacuum vessel, provide all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations and must be manufacturable at low cost. The major components of the cryostat are the vacuum vessel, thermal shields, multilayer insulation (MLI) system, cryogenic piping, interconnections, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course their 25 year expected life. This paper describes the design of the current SSC collider dipole magnet cryostat and includes discussions on the thermal, structural, and dynamic considerations involved in the development of each of the major systems. 7 refs., 4 figs.

  16. SSC 50 mm collider dipole cryostat design

    SciTech Connect

    Nicol, T.H.

    1992-04-01

    The cryostat of a Superconducting Super Collider (SSC) dipole magnet consists of all magnet components except the magnet assembly itself. It serves to support the magnet accurately and reliably within the vacuum vessel, provide all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations, and must be manufacturable at low cost. The major components of the cryostat are the vacuum vessel, thermal shields, multilayer insulation system, cryogenic piping, interconnections, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course of their expected operating life. This paper describes the design of the current SSC dipole magnet cryostat and includes discussions on the structural and thermal considerations involved in the development of each of the major systems.

  17. ASME Code Calculations for the CC Cryostat

    SciTech Connect

    Luther, R.D.; /Fermilab

    1987-11-04

    This engineering note contains the ASHE Code calculations for the CC Cryostat prepared by the manufacturer, Richmond-Lox Equipment Company. Most of these were taken from calculations initially prepared by Fermilab personne1and pub1ished in Eng. Note 68.

  18. Insulation-Testing Cryostat With Lifting Mechanism

    NASA Technical Reports Server (NTRS)

    Fesmire, James; Dokos, Adam; Scholtens, Brekke; Nagy, Zoltan; Augustynowicz, Stanislaw

    2010-01-01

    The figure depicts selected aspects of an apparatus for testing thermal-insulation materials for cryogenic systems at temperatures and under vacuum or atmospheric conditions representative of those encountered in use. This apparatus, called "Cryostat-100," is based on the established cryogen-boil-off calorimeter method, according to which the amount of heat that passes through an insulation specimen to a cryogenic fluid in a container, and thus the effective thermal conductance of the specimen, is taken to be proportional to the amount of the cryogenic fluid that boils off from the container. The design of Cryostat-100 is based partly on, and incorporates improvements over, the design of a similar prior apparatus called "Cryostat-1" described in "Improved Methods of Testing Cryogenic Insulation Materials" (KSC-12107 & KSC- 12108), NASA Tech Briefs, Vol. 24, No. 12 (December 2000), page 46. The design of Cryostat-100 also incorporates the best features of two other similar prior apparatuses called "Cryostat-2" (also described in the cited prior article) and "Cryostat- 4." Notable among the improvements in Cryostat-100 is the addition of a lifting mechanism that enables safe, rapid, reliable insertion and removal of insulation specimens and facilitates maintenance operations that involve lifting. As in Cryostat-1, the cold mass is a vertical stainless-steel cylindrical vessel subdivided into a larger measurement vessel with smaller thermal-guard vessels at both ends. During operation, all three vessels are kept filled with liquid nitrogen near saturation at ambient pressure (temperature .77.4 K). The cold mass of Cryostat-100 has a length of 1 m and diameter of 168 mm. Each specimen has a corresponding nominal length and inner diameter and a nominal thickness of 25.4 mm. Specimens that are shorter and have thicknesses between 0 and 50 mm are also acceptable. Bulk-fill, foam, clam-shell, multilayer insulation, and layered materials can be tested over a very wide range

  19. Polystyrene cryostat facilitates testing tensile specimens under liquid nitrogen

    NASA Technical Reports Server (NTRS)

    Shogan, R. P.; Skalka, R. J.

    1967-01-01

    Lightweight cryostat made of expanded polystyrene reduces eccentricity in a tensile system being tested under liquid nitrogen. The cryostat is attached directly to the tensile system by a special seal, reducing misalignment effects due to cryostat weight, and facilitates viewing and loading of the specimens.

  20. D0 Silicon Upgrade: Cryogenic Line Routing: Refrigerator to VLPC Cryostats & Solenoid

    SciTech Connect

    Rucinski, Russ; /Fermilab

    1994-10-04

    This engineering note documents the proposed cryogenic line routing from the liquid helium (LHe) refrigeration plant to the detector solenoid and VLPC cryostats. Many figures are included to aid in understanding the route. As an appendix, I include some general comments relevant to the topic. Also listed are a number of routing options that were considered before the proposed route was finalized.

  1. Design and Fabrication of Cryostat Interface and Electronics for High Performance Antimatter Trap (HI-PAT)

    NASA Technical Reports Server (NTRS)

    Smith, Gerald A.

    1999-01-01

    Included in Appendix I to this report is a complete set of design and assembly schematics for the high vacuum inner trap assembly, cryostat interfaces and electronic components for the MSFC HI-PAT. Also included in the final report are summaries of vacuum tests, and electronic tests performed upon completion of the assembly.

  2. Paleomagnetism of the Cantabria-Asturias Arc: Kinematics of arc formation and implications for final collisional adjustments within the Pangea supercontinent

    NASA Astrophysics Data System (ADS)

    Weil, Arlo Brandon

    The Cantabria-Asturias Arc (CAA) of SW Europe is a highly curved Variscan belt that formed along the ancient plate boundary between Gondwana and Laurussia during the assembly of Pangea. To construct a viable kinematic and tectonic model for CAA formation, a paleomagnetic, rock magnetic, scanning electron microscopy (SEM) and structural study of two Devonian carbonate formations was undertaken to distinguish the discrete stages of deformation that the are experienced. The combination of these approaches provides a method for dating the complex deformation history experienced by the CAA and sheds new light on the mechanism of orogen-related remagnetizations and, and particularly, arc formation. The Devonian carbonates acquired three late Paleozoic remagnetizations during the Variscan orogeny of northern Spain. Rock magnetic data and SEM analyses reveal that the three late Paleozoic remagnetizations are chemical remanent magnetizations, likely facilitated by the presence of fluids. The fluids, whether externally or internally derived, were activated as a response to orogeny based on the acquisition of remagnetizations subsequent to local Variscan deformation phases. The protracted deformation history increased fluid mobility as a product of tectonic thickening, tectonically induced permeability, and/or gravity-driven flow. The paleomagnetic and structural data show that the CAA experienced true (˜100%) oroclinal bending of an originally linear belt in a two-stage tectonic history. This history represents two regional compression phases: (1) east-west compression in the Late Carboniferous and (2) north-south compression in the Permian (both in present-day coordinates). The later compression phase reflects the northward movement of Gondwana and its final collision with Laurussia. The new paleomagnetic data and this tectonic scenario argue against previously proposed syn-thrusting rotation, wrenching and indentor models for the formation of the CAA, because rotation

  3. Building Bigger, Better Instruments with Dry Cryostats

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.; Voellmer, George

    2010-01-01

    The cylindrical instrument volume allowable n SOFIA is large, comprising perhaps 400 liters at 4K. However, the cryogen accommodation to enable this environment consumes roughly 20% of the volume, and worsens rues, airworthiness/safety, and handling/operation, Present-day pulse tube coolers have negligible cold volumes, provide adequate cooling powers, and reach colder temperatures than stored cryogen. In addition, they permit safer, more reliable, lower maintenance instrument operation. While the advantages of dry cryostats are well-known and commonly used in labs and ground-based astronomical facilities, SOFIA would require some charges in accommodations to permit a pulse tube cooler to operate on board, Whil e these changes are not negligible, we present our investigation into the feasibility and desirability of making SOFIA a dry cryostat-capable observatory

  4. HINS Superconducting Lens and Cryostat Performance

    SciTech Connect

    Page, T.M.; DiMarco, J.; Huang, Y.; Orris, D.F.; Tartaglia, M.A.; Terechkine, I.; Tompkins, J.C.; /Fermilab

    2008-08-01

    Fermi National Accelerator Laboratory is involved in the development of a 60 MeV superconducting linac. This linac is part of the High Intensity Neutrino Source (HINS) R&D Program. The initial beam acceleration in the front end section of the linac is achieved using room temperature spoke cavities, each of which is combined with a superconducting focusing solenoid. These solenoid magnets are cooled with liquid helium at 4.5K, operate at 250 A and have a maximum magnetic field strength of 7.5 T. A prototype solenoid cryostat was built and tested at the Fermilab Magnet Test Facility. This paper discusses the test results of the prototype and compares the measured and estimated performance of the cryostat. We also present the methods and results for measuring and fiducializing the axis of the solenoid lens.

  5. Cryostat including heater to heat a target

    DOEpatents

    Pehl, R.H.; Madden, N.W.; Malone, D.F.

    1990-09-11

    A cryostat is provided which comprises a vacuum vessel; a target disposed within the vacuum vessel; a heat sink disposed within the vacuum vessel for absorbing heat from the detector; a cooling mechanism for cooling the heat sink; a cryoabsorption mechanism for cryoabsorbing residual gas within the vacuum vessel; and a heater for maintaining the target above a temperature at which the residual gas is cryoabsorbed in the course of cryoabsorption of the residual gas by the cryoabsorption mechanism. 2 figs.

  6. Building the BICEP3 Test Cryostat

    NASA Astrophysics Data System (ADS)

    Walker, Samantha; Kuo, Chao-Lin; Thompson, Keith L.; Grayson, James; Karpel, Ethan; Monticue, Val; Kuo Group/Bicep3 Collaboration Team

    2016-03-01

    BICEP3, a ground-based telescope stationed in the South Pole, currently employs a cryostat to observe the polarization of the Cosmic Microwave Background, the earliest light in the Universe, by using devices that take advantage of the superconductivity transition of titanium. The cryostat consists of staggered temperature stages at 300 K, 50 K, 4 K, 2 K, 350 mK, and 250 mK that are maintained by both a pulse tube and three stage helium (He4-He3-He3) sorption refrigerator. However, currently the helium refrigerator is experiencing unanticipated heat loading which is decreasing the fridge cycle hold time and thus the number of hours that BICEP3 can observe for in a given period of time. To address this issue, this past summer I worked at Stanford University to construct a thermally-similar cryostat that will be used to test the thermal conductivities of its various internal components at subKelvin temperatures and determine the source of this heat loading.

  7. Insulation Testing Using Cryostat Apparatus with Sleeve

    NASA Technical Reports Server (NTRS)

    Fesmire, J. E.; Augustynowicz, S. D.

    1999-01-01

    The method and equipment of testing continuously rolled insulation materials is presented in this paper. Testing of blanket and molded products is also facilitated. Materials are installed around a cylindrical copper sleeve using a wrapping machine. The sleeve is slid onto the vertical cold mass of the cryostat. The gap between the cold mass and the sleeve measures less than 1 mm. The cryostat apparatus is a liquid nitrogen boiloff calorimeter system that enables direct measurement of the apparent thermal conductivity (k-value) of the insulation system at any vacuum level between 5 x 10(exp -5) and 760 torr. Sensors are placed between layers of the insulation to provide complete temperature-thickness profiles. The temperatures of the cold mass (maintained at 77.8 kelvin (K)), the sleeve (cold boundary temperature (CBT)), the insulation outer surface (warm boundary temperature (WBT)), and the vacuum can (maintained at 313 K by a thermal shroud) are measured. Plots of CBT, WBT, and layer temperature profiles as functions of vacuum level show the transitions between the three dominant heat transfer modes. For this cryostat apparatus, the measureable heat gain is from 0.2 to 20 watts. The steady-state measurement of k-value is made when all temperatures and the boiloff rate are stable.

  8. A cryostat device for liquid nitrogen convection experiments

    NASA Astrophysics Data System (ADS)

    Dubois, Charles; Duchesne, Alexis; Caps, Herve

    2015-11-01

    When a horizontal layer of expansible fluid heated from below is submitted to a large vertical temperature gradient, one can observe convective cells. This phenomenon is the so-called Rayleigh-Bénard instability. In the literature, this instability is mainly studied when the entire bottom surface of a container heats the liquid. Under these conditions, the development of regularly spaced convective cells in the liquid bulk is observed. Cooling applications led us to consider this instability in a different geometry, namely a resistor immersed in a bath of cold liquid. We present here experiments conducted with liquid nitrogen. For this purpose, we developed a cryostat in order to be able to perform Particle Image Velocimetry. We obtained 2D maps of the flow and observed, as expected, two Rayleigh-Bénard convective cells around the heater. We particularly investigated the vertical velocity in the central column between the two cells. We compared these data to results we obtained with silicone oil and water in the same geometry. We derived theoretical law from classical models applied to the proposed geometry and found a good agreement with our experimental data. This project has been financially supported by ARC SuperCool contract of the University of Liege.

  9. The Safety System of the Herschel Cryostat

    NASA Astrophysics Data System (ADS)

    Langfermann, M.; Jahn, G.; Hohn, R.; Ruehe, W.; Jewell, C.

    2004-06-01

    The cryostat for the `Herschel Space Observatory' for the European Space Agency (ESA) science program, planned for a launch with Ariane 5 in 2007, is designed for 6 days ground hold time and 3.5 years lifetime in orbit. The system comprises two tanks containing about 346 kg of liquid and superfluid Helium, with two cryogenic cold safety valves and burst disks, surrounded by three vapor cooled shields and a vacuum vessel. The safety system is two faults tolerant with three independent paths for pressure relief. The analyses of failure modes and resulting mass flows and the safety elements of the cryogenic system will be discussed.

  10. Capital requirements for the transportation of energy materials: 1979 ARC estimates. Draft final report

    SciTech Connect

    Not Available

    1980-08-13

    This report contains TERA's estimates of capital requirements to transport natural gas, crude oil, petroleum products, and coal in the United States by 1990. The low, medium, and high world-oil-price scenarios from the EIA's Mid-range Energy Forecasting System (MEFS), as used in the 1979 Annual Report to Congress (ARC), were provided as a basis for the analysis and represent three alternative futures. TERA's approach varies by energy commodity to make best use of the information and analytical tools available. Summaries of transportation investment requirements through 1990 are given. Total investment requirements for three modes (pipelines, rails, waterways and the three energy commodities can accumulate to a $49.9 to $50.9 billion range depending on the scenario. The scenarios are distinguished primarily by the world price of oil which, given deregulation of domestic oil prices, affects US oil prices even more profoundly than in the past. The high price of oil, following the evidence of the last year, is projected to hold demand for oil below the recent past.

  11. Final Scientific/Technical Report "Arc Tube Coating System for Color Consistency"

    SciTech Connect

    Buelow, Roger; Jenson, Chris; Kazenski, Keith

    2013-03-21

    DOE has enabled the use of coating materials using low cost application methods on light sources to positively affect the output of those sources. The coatings and light source combinations have shown increased lumen output of LED fixtures (1.5%-2.0%), LED arrays (1.4%) and LED powered remote phosphor systems Philips L-Prize lamp (0.9%). We have also demonstrated lifetime enhancements (3000 hrs vs 8000 hrs) and shifting to higher CRI (51 to 65) in metal halide high intensity discharge lamps with metal oxide coatings. The coatings on LEDs and LED products are significant as the market is moving increasingly more towards LED technology. Enhancements in LED performance are demonstrated in this work through the use of available materials and low cost application processes. EFOI used low refractive index fluoropolymers and low cost dipping processes for application of the material to surfaces related to light transmission of LEDs and LED products. Materials included Teflon AF, an amorphous fluorinated polymer and fluorinated acrylic monomers. The DOE SSL Roadmap sets goals for LED performance moving into the future. EFOI's coating technology is a means to shift the performance curve for LEDs. This is not limited to one type of LED, but is relevant across LED technologies. The metal halide work included the use of sol-gel solutions resulting in silicon dioxide and titanium dioxide coatings on the quartz substrates of the metal halide arc tubes. The coatings were applied using low cost dipping processes.

  12. The CUORE cryostat: commissioning and performance

    NASA Astrophysics Data System (ADS)

    Singh, V.; Alduino, C.; Alessandria, F.; Bersani, A.; Biassoni, M.; Bucci, C.; Caminata, A.; Canonica, L.; Cappelli, L.; Cereseto, R.; Chott, N.; Copello, S.; Cremonesi, O.; Cushman, J. S.; D’Addabbo, A.; Davis, C. J.; Dell’Oro, S.; Drobizhev, A.; Franceschi, M. A.; Gladstone, L.; Gorla, P.; Guetti, M.; Ligi, C.; Napolitano, T.; Nucciotti, A.; Orlandi, D.; Ouellet, J. L.; Pagliarone, C. E.; Pattavina, L.; Rusconi, C.; Santone, D.; Taffarello, L.; Terranova, F.; Wallig, J.; Wise, T.; Uttaro, S.

    2016-05-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) will search for the 0vββ decay in 130Te using a cryogenic array of TeO2 bolometers, operated at a base temperature of ~10mK. CUORE will consist of a closely packed array of 19 towers each containing 52 crystals, for a total mass of 741kg. The detector assembly is hosted in one of the largest cryostats ever constructed and will be cooled down to base temperature using a custom-built cryogen free dilution refrigerator. The CUORE cryostat along with the pulse tube based dilution refrigerator has been already commissioned at Laboratori Nazionali del Gran Sasso (LNGS) and a record base temperature, on a cubic meter scale, of ~6mK was achieved during one of the integration runs. We present the results from integration runs, characterizing the system and the cooling performance of the dilution refrigerator, effectively showcasing its stability at base temperature for the expected thermal load.

  13. Heat transfer design and performance of a helium cryostat operating at 6.5 K

    SciTech Connect

    Gasteyer, T.H.; Krempetz, K.J.; Lee, A.; Rucinski, R.A.; Stefanik, A.M.

    1994-12-31

    A liquid helium cryostat has been designed and operated for the purpose of testing visible light photon counter (VLPC) chips at 6.5 K. To achieve the desired operational characteristics for the VLPC devices their operating temperature is restricted to 6.5 K +/{minus} 0.1 K. They will be used in a scintillating fiber tracker being proposed as part of an upgrade of the D(0) detector at Fermilab. The final version of the scintillating fiber tracker will contain roughly 100,000 VLPC channels. Two cryostats with identical thermal design (a 128 channel and a 3072 channel design) have been built to perform the initial VLPC testing. The heat transfer needed to maintain the VLPC at its operating temperature occurs by conduction across an annular helium gas gap to a liquid helium reservoir. Helium boiloff is used to intercept conduction heat leak to the liquid reservoir. ANSYS finite element heat transfer analysis was utilized in the thermal design of the cryostat. The cryostat design and thermal performance (predicted and measured) are presented.

  14. Extreme argon purity in a large, non-evacuated cryostat

    SciTech Connect

    Tope, Terry; Adamowski, Mark; Carls, B.; Hahn, A.; Jaskierny, W.; Jostlein, H.; Kendziora, C.; Lockwitz, S.; Pahlka, B.; Plunkett, R.; Pordes, S.; Rebel, B.; Schmitt, R.; Skup, E.; Stancari, M.; Yang, T.

    2014-01-29

    Liquid Argon Time Projection Chambers (LArTPCs) show promise as scalable devices for the large detectors needed for long-baseline neutrino oscillation physics. Over the last several years at Fermilab a staged approach to developing the technology for large detectors has been developed. The TPC detectors require ultra-pure liquid argon with respect to electronegative contaminants such as oxygen and water. The tolerable electronegative contamination level may be as pure as 60 parts per trillion of oxygen. Three liquid argon cryostats operated at Fermilab have achieved the extreme purity required by TPCs. These three cryostats used evacuation to remove atmospheric contaminants as the first purification step prior to filling with liquid argon. Future physics experiments may require very large detectors with tens of kilotonnes of liquid argon mass. The capability to evacuate such large cryostats adds significant cost to the cryostat itself in addition to the cost of a large scale vacuum pumping system. This paper describes a 30 ton liquid argon cryostat at Fermilab which uses purging to remove atmospheric contaminants instead of evacuation as the first purification step. This cryostat has achieved electronegative contamination levels better than 60 parts per trillion of oxygen equivalent. The results of this liquid argon purity demonstration will strongly influence the design of future TPC cryostats.

  15. Cryostat Filling Limitations for Proposed Ar Dewar Pressure Increase

    SciTech Connect

    Dixon, K.; Wu, J.; /Fermilab

    1991-07-23

    In order to significantly decrease the amount of time required to fill the cryostats, it is desired to raise the setpoint of the 'operating' relief valve on the argon storage dewar to 20 psig from its existing 16 psig setting. This additional pressure increases the flow to the cryostats and will overwhelm the relief capacity if the temperature of the modules within these vessels is warm enough. Using some conservative assumptions and simple calculations within this note, the maximum average temperature that the modules within each cryostat can be at prior to filling from the storage dewar with liquid argon is at least 290 K.

  16. Design Evolution and Analysis of the ITER Cryostat Support System

    NASA Astrophysics Data System (ADS)

    Xie, Han; Song, Yuntao; Wang, Songke

    2015-12-01

    The cryostat is a vacuum tight container enveloping the entire basic systems of the ITER tokamak machine, including a vacuum vessel, a superconducting magnet and thermal shield etc. It is evacuated to a pressure of 10-4 Pa to limit the heat transfer via gas conduction and convection to the cryogenically cooled components. Another important function of cryostat is to support all the loads from the tokamak to the concrete floor of the pit by its support system during different operational regimes and accident scenarios. This paper briefly presents the design evolution and associated analysis of the cryostat support system and the structural interface with the building.

  17. D-Zero Cryostat Supplemental Rupture Disc

    SciTech Connect

    Mulholland, G.T.; /Fermilab

    1987-08-03

    The common relief and rupture disc vent line requires a double disc assembly with vented interspace for accurate disc burst pressures. The first disc must take pump and purge vacuum loading, but be set to operate at 110% of the MAWP, 18.3 psig (ASME code). The available solution is 18.3 psig with a burst tolerance of +/- psig. The interspace should be locally vented by a flow limiting vent valve to decouple the vent line backpressure from the vessel rupture disc. The second disc must take the worst case vent line backpressure, the steady state value found in D-Zero engineering note 3740.000-EN-63 with all three cryostats simultaneously venting at the fire condition into the 4-inch x 6-inch and 6-inch x 8-inch sections. This value is less than 2 psid. The maximum rupture value for the second disc must be less than the minimum rupture value for the first disc less 2 psid i.e. < 16.3.

  18. Series-Produced Helium II Cryostats for the Lhc Magnets: Technical Choices, Industrialisation, Costs

    NASA Astrophysics Data System (ADS)

    Poncet, A.; Parma, V.

    2008-03-01

    Assembled in 8 continuous segments of approximately 2.7 km length each, the He II cryostats for the 1232 cryodipoles and 474 Short Straight Sections (SSS housing the quadrupoles) must fulfill tight technical requirements. They have been produced by industry in large series according to cost-effective industrial production methods to keep expenditure within the financial constraints of the project and assembled under contract at CERN. The specific technical requirements of the generic systems of the cryostat (vacuum, cryogenic, electrical distribution, magnet alignment) are briefly recalled, as well as the basic design choices leading to the definition of their components (vacuum vessels, thermal shielding, supporting systems). Early in the design process emphasis was placed on the feasibility of manufacturing techniques adequate for large series production of components, optimal tooling for time-effective assembly methods, and reliable quality assurance systems. An analytical review of the costs of the cryostats from component procurement to final assembly, tests and interconnection in the machine is presented and compared with initial estimates, together with an appraisal of the results and lessons learned.

  19. Test VLPC Cryostat: Programming and Configuration of Cryogenic and Temperature Instruments

    SciTech Connect

    Zaczek, M.; /Fermilab

    1997-08-11

    Currently, Fermi National Accelerator Laboratory is in the midst of a site wide upgrade. Here at D-Zero, one of the components of this upgrade will be the construction of two 48 cassette VLPC cryostats which will be the heart of the new magnetic central fiber tracker. A VLPC or Visible Light Photon Counter is a device that allows physicists to more accurately calculate the origins of particles ejected during a proton - anti-proton collision in the detector. Inside the detector is an optical fiber barrel which surrounds the collision point. When an ejected particle strikes a fiber the result is the release of photons which travel along the fiber until they reach the bottom of a cassette hitting the VLPC chip. These impacts result in voltages which are read by the VLPC chips and sent to the computer for future analysis. From these voltages, physicists can determine the origins of the particles, their charges, their speeds and other information as well. Within the last few months a test VLPC bas been built at D-Zero. This VLPC is comprised of four rectangular cassettes each equipped with heating elements, RTDs and 1024 VLPC chips. This particular configuration is unique here at Fermilab. Other VLPC cryostats that have been built were usually cylindrical in their geometry. The purpose of this test VLPC is to have on hand a reliable model to aid in understanding the complexities involved in running such devices at approximately 10K, as well as to prepare for the eventual 48 cassette VLPCs to come. In particular, an important aspect of this test phase is to check the engineering involved so that the final cryostats are designed correctly. Also, this test cryostat will enable us to check each of the cassettes to be used in the final cryostat and correct any problems before hand. This engineering note has been written in order to describe the setup of the VLPC as it pertains to the programming, configuration and control of all of the cryogenic and temperature instruments

  20. First scientific application of the membrane cryostat technology

    SciTech Connect

    Montanari, David; Adamowski, Mark; Baller, Bruce R.; Barger, Robert K.; Chi, Edward C.; Davis, Ronald P.; Johnson, Bryan D.; Kubinski, Bob M.; Najdzion, John J.; Rucinski, Russel A.; Schmitt, Rich L.; Tope, Terry E.; Mahoney, Ryan; Norris, Barry L.; Watkins, Daniel J.; McCluskey, Elaine G.; Stewart, James

    2014-01-29

    We report on the design, fabrication, performance and commissioning of the first membrane cryostat to be used for scientific application. The Long Baseline Neutrino Experiment (LBNE) has designed and fabricated a membrane cryostat prototype in collaboration with IHI Corporation (IHI). Original goals of the prototype are: to demonstrate the membrane cryostat technology in terms of thermal performance, feasibility for liquid argon, and leak tightness; to demonstrate that we can remove all the impurities from the vessel and achieve the purity requirements in a membrane cryostat without evacuation and using only a controlled gaseous argon purge; to demonstrate that we can achieve and maintain the purity requirements of the liquid argon during filling, purification, and maintenance mode using mole sieve and copper filters from the Liquid Argon Purity Demonstrator (LAPD) R and D project. The purity requirements of a large liquid argon detector such as LBNE are contaminants below 200 parts per trillion oxygen equivalent. This paper gives the requirements, design, construction, and performance of the LBNE membrane cryostat prototype, with experience and results important to the development of the LBNE detector.

  1. Continuous Flow Cryostat for X-Ray Fluorescence

    SciTech Connect

    Weng, T.-C.; Linden, Peter J. E. M. van der; Glatzel, Pieter; Lapras, Christophe; Krzyzowski, Michael

    2010-06-23

    A continuous Helium flow cryostat was designed and built by Cryovac GMbH to specifications given by ESRF beamline ID26. The beamline has constructed a high energy resolution X-ray emission spectrometer using multiple spherically bent analyser crystals, together with the sample and detector on a vertical Rowland circle. The double shrouded cryostat has a low profile designed to fit into the spectrometer setup, the lowest detector position allows for a Bragg angle of 85 degrees with a 1 meter diameter Rowland circle. The cryostat has a temperature range of 5 to 300 Kelvin on the sample holder which is cooled by static Helium exchange gas. The cryostat has triple windows for beam entrance, transmission and fluorescence; the latter offers an opening angle of 80 degrees horizontally and 50 degrees vertically. The cryostat can be configured to work in two different operation modes: translation or rotation. The translation mode offers a displacement of 50 mm to accommodate multiple samples on the sample holder. The rotation mode is used for polarisation studies on single crystals.We show recent results obtained on Chromium containing molecular complexes; data collection was done at a temperature of 10 Kelvin to avoid radiation damage.

  2. A closed-cycle 1 K refrigeration cryostat

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Lichtenwalter, Ben; Friebel, Aaron; Tang, Hong X.

    2014-11-01

    A 1 K closed-cycle cryostat has been developed to provide continuous cooling to a photon detector below 2 K. A two-stage 4 K pulse tube cryocooler is used to liquefy evacuated vapor from a 1 K pumping port to form a closed-cycle refrigeration loop. A 1 K instrumentation chamber, attached to the 1 K cooling station, is designed to operate with helium inside and provide more uniform cooling. The design of the cryostat has no direct mechanical contact between the pulse tube cryocooler heat exchangers and the 1 K cooling station resulting in almost no vibration transfer to instrumentation chamber. The cryostat can reach a no-load temperature of 1.62 K and provide 250 mW cooling power at 1.84 K.

  3. Results of the BETS Survey of the CC Cryostat

    SciTech Connect

    Luther, R.D.; /Fermilab

    1988-01-07

    This Engineering Note presents results of dimensional surveys of the CC Cryostat. The surveys were performed by members of the Fermilab Alignment Group using a computerized optical system known as BETS. The coordinate system used is described on page 1 of the note. Locations of the support bosses in the inner vessel are given on pages 2 and 3. The bosses control the position of the module array within the cryostat. Locations of the center cylinders (bores) and bypass tubes in both vessels are given on pages 2 and 4 through 6. Elevations and locations of the nozzles on top of the cryostat are given on page 9. Measurements of the stack-up heights of the support stanchions are given on page 13. Raw BETS data are included in Appendix A of the Note.

  4. Welding arc plasma physics

    NASA Technical Reports Server (NTRS)

    Cain, Bruce L.

    1990-01-01

    The problems of weld quality control and weld process dependability continue to be relevant issues in modern metal welding technology. These become especially important for NASA missions which may require the assembly or repair of larger orbiting platforms using automatic welding techniques. To extend present welding technologies for such applications, NASA/MSFC's Materials and Processes Lab is developing physical models of the arc welding process with the goal of providing both a basis for improved design of weld control systems, and a better understanding of how arc welding variables influence final weld properties. The physics of the plasma arc discharge is reasonably well established in terms of transport processes occurring in the arc column itself, although recourse to sophisticated numerical treatments is normally required to obtain quantitative results. Unfortunately the rigor of these numerical computations often obscures the physics of the underlying model due to its inherent complexity. In contrast, this work has focused on a relatively simple physical model of the arc discharge to describe the gross features observed in welding arcs. Emphasis was placed of deriving analytic expressions for the voltage along the arc axis as a function of known or measurable arc parameters. The model retains the essential physics for a straight polarity, diffusion dominated free burning arc in argon, with major simplifications of collisionless sheaths and simple energy balances at the electrodes.

  5. A top loading 2 Kelvin test cryostat for SRF cavities.

    SciTech Connect

    Kedzie, M.; Kelly, M. P.; Gerbick, S. M.; Fuerst, J. D.; Shepard, K. W.; Physics

    2009-01-01

    A new large 2 Kelvin test cryostat is being commissioned at Argonne National Laboratory. This system will have a full time connection to the 4.5 Kelvin ATLAS refrigerator and, with integrated J-T heat exchanger, will allow continuous 2 Kelvin operation. The large diameter was chosen to accommodate essentially all of today's superconducting cavities and the top loading design facilitates clean room assembly. The commissioning run will be with a coaxial half wave cavity to be followed by testing with 1.3 GHz single-cell elliptical cavities. Details of the initial engineering cool down on the cryostat are presented.

  6. Lazy arc consistency

    SciTech Connect

    Schiex, T.; Gaspin, C.; Regin, J.C.; Verfaillie, G.

    1996-12-31

    Arc consistency filtering is widely used in the framework of binary constraint satisfaction problems: with a low complexity, inconsistency may be detected and domains are filtered. In this paper, we show that when detecting inconsistency is the objective, a systematic domain filtering is useless and a lazy approach is more adequate. Whereas usual arc consistency algorithms produce the maximum arc consistent sub-domain, when it exists, we propose a method, called LAC{tau}, which only looks for any arc consistent sub-domain. The algorithm is then extended to provide the additional service of locating one variable with a minimum domain cardinality in the maximum arc consistent sub-domain, without necessarily computing all domain sizes. Finally, we compare traditional AC enforcing and lazy AC enforcing using several benchmark problems, both randomly generated CSP and real life problems.

  7. Majorana One-Tonne Cryostat Cooling Conceptual Feasibility Study

    SciTech Connect

    Reid, Douglas J.; Orrell, John L.; Fast, James E.; Aguayo Navarrete, Estanislao

    2011-02-17

    This report evaluates the conceptual plans for a one-tonne (S4) cryostat cooling design. This document is based upon previous design work and experimental results used to evaluate the current MAJORANA DEMONSTRATOR (MJD) thermal design. A feasibility study of a cooling system for S4 based on the MJD thermosyphon experiment is presented. The one-tonne experiment will be a scaled up version of the MJD. There will be many cryostats for the S4 experiment. In this document a cryostat with up to 19 strings of Germanium crystals is analyzed. Aside from an extra outer ring of crystals, the geometry of both systems’ cryostats is very similar. The materials used in the fabrication of both ultra-low background experiments will be underground electroformed copper. The current MJD uses a two-phase liquid-gas cooling system to ensure constant operating temperature. This document presents a theoretical investigation of a cooling system for the S4 experiment and evaluates the heat transfer performance requirements for such a system.

  8. Two low-cost, modular sub-λ test cryostats

    SciTech Connect

    Fuerst, J. D.; Kaluzny, J. A.

    2014-01-29

    Two general-purpose liquid helium (LHe) test cryostats have been developed in support of a major upgrade to the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The cryostats are capable of sustained operation below 1.8 K and currently support tests of prototype superconducting rf (srf) cavities for the APS Upgrade’s Short Pulse X-ray (SPX) initiative. To save cost, two existing test vessels were reconditioned: one “bucket dewar” supporting bare cavity tests and one shielded vacuum vessel with an integral LHe reservoir for jacketed/dressed cavity tests. A new feedbox containing a heat exchanger and associated valves was also designed and fabricated to support either cryostat. The resulting modular design permits tests on a wide variety of srf cavities in various states of completion, minimizing cost and maximizing use of the hardware. Together with a dedicated vacuum pump, control system, and helium supply via storage dewar or cryoplant, these cryostats are vital to the srf cavity development effort within the APS Upgrade.

  9. Development of membrane cryostats for large liquid argon neutrino detectors

    NASA Astrophysics Data System (ADS)

    Montanari, D.; Bremer, J.; Gendotti, A.; Geynisman, M.; Hentschel, S.; Loew, T.; Mladenov, D.; Montanari, C.; Murphy, S.; Nessi, M.; Norris, B.; Noto, F.; Rubbia, A.; Sharma, R.; Smargianaki, D.; Stewart, J.; Vignoli, C.; Wilson, P.; Wu, S.

    2015-12-01

    A new collaboration is being formed to develop a multi-kiloton Long-Baseline neutrino experiment that will be located at the Surf Underground Research Facility (SURF) in Lead, SD. In the present design, the detector will be located inside cryostats filled with 68,400 ton of ultrapure liquid argon (less than 100 parts per trillion of oxygen equivalent contamination). To qualify the membrane technology for future very large-scale and underground implementations, a strong prototyping effort is ongoing: several smaller detectors of growing size with associated cryostats and cryogenic systems will be designed and built at Fermilab and CERN. They will take physics data and test different detector elements, filtration systems, design options and installation procedures. In addition, a 35 ton prototype is already operational at Fermilab and will take data with single-phase detector in early 2016. After the prototyping phase, the multi-kton detector will be constructed. After commissioning, it will detect and study neutrinos from a new beam from Fermilab. These cryostats will be engineered, constructed, commissioned, and qualified by an international engineering team. This contribution presents the on-going effort on the development of the cryostats and details the requirements and the current status of the design.

  10. Variable-Temperature Cryostat For Radiation-Damage Testing Of Germanium Detectors

    NASA Technical Reports Server (NTRS)

    Floyd, Samuel R.; Puc, Bernard P.

    1992-01-01

    Variable-temperature cryostats developed to study radiation damage to, and annealing of, germanium gamma-ray detectors. Two styles: one accommodates large single detector and one accommodates two medium-sized detectors. New cryostats allow complete testing of large-volume germanium gamma-ray detectors without breaking cryostat vacuum and removing detectors for annealing.

  11. Cathodic arcs

    SciTech Connect

    Anders, Andre

    2003-10-29

    Cathodic arc plasma deposition has become the technology of choice for hard, wear and corrosion resistant coatings for a variety of applications. The history, basic physics of cathodic arc operation, the infamous macroparticle problem and common filter solutions, and emerging high-tech applications are briefly reviewed. Cathodic arc plasmas standout due to their high degree of ionization, with important consequences for film nucleation, growth, and efficient utilization of substrate bias. Industrial processes often use cathodic arc plasma in reactive mode. In contrast, the science of arcs has focused on the case of vacuum arcs. Future research directions include closing the knowledge gap for reactive mode, large area coating, linear sources and filters, metal plasma immersion process, with application in high-tech and biomedical fields.

  12. Gas permeation and performance of an FRP cryostat

    NASA Astrophysics Data System (ADS)

    Okada, Toichi; Nishijima, Shigehiro; Fujioka, Kouji; Kuraoka, Yasurou

    The causes of degradation in the vacuum within an FRP cryostat, a device useful in aerospace engineering because of its light weight, were studied experimentally from a materials science standpoint. It was found that gas diffusion practically does not occur at cryogenic temperatures. When gas permeation is induced at low temperatures, the main result is a gas leak due to a crack caused by thermal shock or thermal contraction. Reducing the bubbles in the FRP material during its manufacture should increase its crack resistance. Gas diffusion is a problem at room temperature because the helium gas diffusion rate is large considering the degree of vacuum. Increasing the glass content decreases the diffusion rate. Outgassing from FRP consists mainly of water from the FRP material. Baking reduces the water content in the FRP and increases its suitability for cryostats.

  13. Cryostat "UV" Relief Valve Selection and Process Flow

    SciTech Connect

    Mulholland, G.T.; Wintercorn, S.J.; /Fermilab

    1987-08-11

    This report describes the selection of the relief valves for the D-Zero cryostats. The selection was based on the flow requirements calculated in D-Zero engineering note 3740.214,224-EN-6 under fire conditions (1200 F, no vacuum) for the central cryostat; 264 SCFM. This value was calculated from section 5.3.5 of 'Pressure Relief Device Standards; S 1.3-Compressed Gas Storage Containers', published by the Compressed Gas Association, Inc. The flow calculated above is far greater than the required fire condition flow capacity of 264 SCFM. The improbable 70 F flow temperature value of 738 SCFM is still much greater than the required fire capacity. The flow capacity of the paralleled supplemental rupture disc is 2640 SCFM, independently greater than the fire condition flow requirement.

  14. Preliminary design of the CIT (Compact Ignition Tokamak) cryostat

    SciTech Connect

    Goins, M.L.

    1989-01-01

    For the Compact Ignition Tokamak (CIT) to achieve the performance goals set forth, the toroidal field (TF) and poloidal field (PF) coil systems must operate in a cryogenic temperature regime. The cryostat has been designed to provide and maintain this environment. The preliminary design activity is addressing the design issues and interfaces necessary to provide a cryogenic vessel that will maintain a maximum temperature differential of 8{degree}C between the outer vessel wall and the ambient test cell conditions; operate in a pressure range of +5 psig to {minus}2 psig; accommodate numerous penetrations, including cooling, diagnostic, and gravity support items; and maintain a maximum leak rate of gaseous nitrogen at 1 l/s at 1 atm. Conceptually, the cryostat consists of thermal insulation sandwiched between an inner primary stainless steel pressure vessel and a thin outer stainless steel wall. Design activities have concentrated on determining the size and shape of the primary vessel wall and selecting the best candidate thermal insulation materials for future irradiation testing. The following shapes of the upper and lower cryostat structure were analyzed: a standard ASME torispherical domed top and bottom; a nonstandard domed top and bottom; and a 2{degree} sloped conical top and bottom contour. Screening of candidate insulation materials was based on lowest thermal conductivity over the range of temperatures anticipated in the CIT environment; low material cost and apparent ease of assembly; and survivability of material in the CIT irradiation environment. This paper presents the configuration development of the cryostat used to maintain the cryogenic temperature environment for CIT. 3 refs., 3 figs., 3 tabs.

  15. Initial Component Testing for a Germanium Array Cryostat

    SciTech Connect

    Keillor, Martin E.; Aalseth, Craig E.; Day, Anthony R.; Fast, James E.; Hoppe, Eric W.; Hyronimus, Brian J.; Hossbach, Todd W.; Seifert, Allen

    2009-06-01

    This report describes progress on the construction of two ultra-low-background cryostats that are part of the NA-22 funded “Radionuclide Laboratories” (RN Labs) project. Each cryostat will house seven high-purity germanium crystals (HPGe). These cryostats are being built from a limited set of materials that are known to have very low levels of radioactive impurities. The RN Labs instrument is designed to take advantage of low background performance, high detection efficiency, and γ-γ coincidence signatures to provide unprecedented gamma spectroscopy sensitivity. The project is focused on improving gamma analysis capabilities for nuclear detonation detection (NDD) applications. The instrument also has the potential for basic nuclear physics research. Section 1 provides the background for the project. Section 2 discusses germanium crystal acceptance testing. Design problems were found after the first delivery of new detectors from the vendor, Canberra Semiconductors. The first four crystals were returned for repair, resulting in a delay in crystal procurement. Section 3 provides an update on copper electroforming. In general, electroforming parts for RN Labs has proceeded smoothly, but there have been recent problems in electroforming three large copper parts necessary for the project. Section 4 describes the first round of testing for the instrument: anti-cosmic scintillator testing, electronics testing, and initial vacuum testing. Section 5 concludes with an overall description of the state of the project and challenges that remain.

  16. Superfluid helium cryostat for the SIRTF cryogenic telescope assembly

    NASA Astrophysics Data System (ADS)

    Volz, Stephen M.; Schweickart, Russell B.; Heurich, Bruce

    2003-03-01

    The Space Infrared Telescope Facility (SIRTF) is the last of NASA's four great observatories, scheduled for launch in January 2003. At the heart of the SIRTF Observatory is the Cryogenic Telescope Assembly (CTA) that provides a 1.4 K heat sink for the SIRTF Science Instruments while cooling the telescope to as low as 5.5 K in order to achieve thea low photon background. This unique cryogenic/thermal system provides the necessary cooling through passive means combined with vapor cooling by the helium gas vented from a 360 liter superfluid helium cryostat. The passive cooling is made possible by the favorable thermal environment achieved in an Earth-trailing solar orbit, with the payload millions of miles from the Earth. The SIRTF Cryostat and integrated CTA have just completed an extended period of cryogenic system performance testing. This testing included mission lifetime assessment, luanch hold capability and in situ characterization and performance measurements of the porous plug liquid-vapor phase separator. We also encountered and recovered from an ice contamination incident within the cryostat. We report here the system and component test results. We also provide recommendations and lessons learned through the operations of the SIRTF system.

  17. Recirculating 1-K-Pot for Pulse-Tube Cryostats

    NASA Technical Reports Server (NTRS)

    Paine, Christopher T.; Naylor, Bret J.; Prouve, Thomas

    2013-01-01

    A paper describes a 1-K-pot that works with a commercial pulse tube cooler for astrophysics instrumentation testbeds that require temperatures <1.7 K. Pumped liquid helium-4 cryostats were commonly used to achieve this temperature. However, liquid helium-4 cryostats are being replaced with cryostats using pulse tube coolers. The closed-cycle 1K-pot system for the pulse tube cooler requires a heat exchanger on the pulse tube, a flow restriction, pump-out line, and pump system that recirculates helium-4. The heat exchanger precools and liquefies helium- 4 gas at the 2.5 to 3.5 K pulse tube cold head. This closed-cycle 1-K-pot system was designed to work with commercially available laboratory pulse tube coolers. It was built using common laboratory equipment such as stainless steel tubing and a mechanical pump. The system is self-contained and requires only common wall power to operate. The lift of 15 mW at 1.1 K and base temperature of 0.97 K are provided continuously. The system can be scaled to higher heat lifts of .30 to 50 mW if desired. Ground-based telescopes could use this innovation to improve the efficiency of existing cryo

  18. Construction of a Para-Ortho Hydrogen Test Cryostat

    NASA Astrophysics Data System (ADS)

    Essler, J.; Haberstroh, Ch.

    2010-04-01

    In a prospective hydrogen economy it is necessary to verify the para concentration of the employed hydrogen. In case of a short storage time of about a few days only it has been shown that a partial conversion into para-hydrogen gives an optimized overall efficiency. Hence, an easy and reliable method of measuring the para-hydrogen concentration is needed. In this paper, the concept and construction of a small test cryostat are described and first results are presented. The measuring principle is based on a catalytic induced adiabatic ortho-para conversion of a hydrogen gas flow starting from a known temperature. The operation of the system only requires a certain amount of liquid nitrogen as coolant. To determine the concentration of para-hydrogen it is only necessary to measure the temperature of the gas before and after the adiabatic catalyst cell. The measuring cryostat is used for further investigation of the spontaneous para-ortho conversion in the supercritical state. In addition, the design of the cryostat allows the investigation of different catalyst materials regarding the catalytic activity and possible degradation by using a known para concentration for the measurement.

  19. Beam to Shell Temperature Differencees for the CC Cryostat

    SciTech Connect

    Luther, R.; /Fermilab

    1991-02-05

    This note documents the calculation of stresses resulting from temperature differences between the CC cryostat shell and the module array support beams, and the calculation of corresponding maximum allowable temperature differences to be monitored during the cooldown of the cryostat. A finite element model of a portion of the inner vessel shell was analyzed for a uniform temperature change. The shell was assumed to be completely restrained by the support beams. A maximum allowable temperature difference was determined based on limits on secondary stress ranges prescribed by the ASME Code (Section VID, Division 2). The maximum allowable difference between the cryostat shell and the support beams was found to vary from about 18K near room temperature to about 30K as the shell temperature approaches liquid argon temperature. The allowable values are tabulated below and plotted in Figure 1. The variation results from the decrease in the coefficient of thermal expansion of stainless steels at lower temperatures. As shown in the plot, the variation is roughly linear. Note that although the shell is assumed to be at the lower temperature in Fig. 1, the limitation on temperature difference will also apply during warmup, when the shell will likely be warmer than the beams.

  20. Evaluation of ASD systems for electric arc furnace and argon oxygen decarburization refiner baghouse fans. Final report

    SciTech Connect

    1997-11-01

    Adjustable speed drive (ASD) control of the baghouse fans for Electric Arc Furnace (EAF) and Argon Oxygen Decarburization Vessel (AOD) can improve operations, reduce the degree of dust generation, and provide significant energy savings. The purpose of the project was to quantify the benefits, both in energy savings and other process improvements and to demonstrate the methodology of applying adjustable speed drives, to two baghouse fans from a system perspective. The report describes the approach to accomplishing the ASD equipment installation, the test procedure and methodology and provides the test results and economic return. The test results indicated that by using ASDs to control the extraction fan air flow for the EAF and AOD, the following benefits would be achieved on an annual basis: EAF annual energy savings, 267,929 kWh valued at $11,575; EAF dust reduction, overall, 2--3%; EAF dust reduction, during the flatbath period, 35%; and AOD annual energy savings, 1,443,078 kWh valued at $62,341.

  1. Nomenclature of SLC Arc beamline components

    SciTech Connect

    Silva, J.; Weng, W.T.

    1986-04-10

    This note defines I and C formal names for beamline components in the Arc as specified in the TRANSPORT decks ARCN FINAL and ARCS FINAL of June 5, 1985. The formal name consists of three fields: the primary name, the zone and the unit number. The general principles and guidelines are explained in Reference 1. The rationale and the final resolutions of the naming conventions for the Arc are explained.

  2. Cryostat system for investigation on new neutron moderator materials at reactor TRIGA PUSPATI

    NASA Astrophysics Data System (ADS)

    Dris, Zakaria bin; Mohamed, Abdul Aziz bin; Hamid, Nasri A.; Azman, Azraf; Ahmad, Megat Harun Al Rashid Megat; Jamro, Rafhayudi; Yazid, Hafizal

    2016-01-01

    A simple continuous flow (SCF) cryostat was designed to investigate the neutron moderation of alumina in high temperature co-ceramic (HTCC) and polymeric materials such as Teflon under TRIGA neutron environment using a reflected neutron beam from a monochromator. Cooling of the cryostat will be carried out using liquid nitrogen. The cryostat will be built with an aluminum holder for moderator within stainless steel cylinder pipe. A copper thermocouple will be used as the temperature sensor to monitor the moderator temperature inside the cryostat holder. Initial measurements of neutron spectrum after neutron passing through the moderating materials have been carried out using a neutron spectrometer.

  3. Very low force cooling contacts for the ISO cryostat cover

    NASA Astrophysics Data System (ADS)

    Schaellig, R.; Seidel, A.

    1990-03-01

    The infrared Space Observatory (ISO) cryostat cover, which will be ejected from the satellite after a period of 10-15 days in orbit, needs passive cooling of its thermal shields to minimize heat input to the cryostat and to maintain a temperature on the innermost shield of 25 K or less. This passive cooling is provided by spring loaded thermal contacts which are also used for ejection of the cover after release of the clampband device that keeps the cover closed during launch. So as not to disturb the satellite attitude control and to limit the load on the mechanical cover shield supports, the force of a single thermal contact was limited to 25-35 N. An experimental program was conducted to measure the thermal contact conductance of various combinations of two shapes and three materials. Typical measured conductance and heat transfer coefficients for the gold treated copper sphere/flat aluminum plane combination are: 2.54 W/sq cm K and 1.8 mW/K at a contact temperature of 8 K and a force of 25 N, with a pressure of 3.5 x 10 to the 8th Pa.

  4. Design of the multilayer insulation system for the Superconducting Super Collider 50mm dipole cryostat

    SciTech Connect

    Boroski, W.N.; Nicol, T.H.; Schoo, C.J.

    1991-03-01

    The development of the multilayer insulation (MLI) system for the Superconducting Super Collider (SSC) 50 mm collider dipole cryostat is an ongoing extension of work conducted during the 40 mm cryostat program. While the basic design of the MLI system for the 50 mm cryostat resembles that of the 40 mm cryostat, results from measurements of MLI thermal performance below 80K have prompted a re-design of the MLI system for the 20K thermal radiation shield. Presented is the design of the MLI system for the 50 mm collider dipole cryostat, with discussion focusing on system performance, blanket geometry, cost-effective fabrication techniques, and built-in quality control measures that assure consistent thermal performance throughout the SSC accelerator. 16 refs., 8 figs., 2 tabs.

  5. Passive vibration isolation for SITELLE's closed cycle cooled cryostats

    NASA Astrophysics Data System (ADS)

    Baril, Marc; Benedict, Tom; Barrick, Gregory; Ho, Kevin

    2012-09-01

    The SITELLE Imaging Fourier Transform Spectrometer system being developed by l'Université Laval at ABB-Bomem will require two identical CCD detector systems. Our requirements for the cryogenic system for these cameras are: cooling to below 190 K, extremely low vibrational input from the cryogenic system (<1 mg RMS from 0-2 kHz), hands-off operation over long periods of time and low original capital outlay and continued operation cost. These constraints drove towards the selection of a Polycold PCC cooled system which exhibits relatively low vibrational noise and can efficiently achieve the required cooling power in our target temperature range. This paper will present work performed to passively mitigate high frequency vibrations imparted by the Polycold PCC cryo-head on the detector cryostat.

  6. Mu2e production solenoid cryostat conceptual design

    SciTech Connect

    Nicol, T.H.; Kashikhin, V.V.; Page, T.M.; Peterson, T.J.; /Fermilab

    2011-06-01

    Mu2e is a muon-to-electron conversion experiment being designed by an international collaboration of more than 65 scientists and engineers from more than 20 research institutions for installation at Fermilab. The experiment is comprised of three large superconducting solenoid magnet systems, production solenoid (PS), transport solenoid (TS) and detector solenoid (DS). A 25 kW, 8 GeV proton beam strikes a target located in the PS creating muons from the decay of secondary particles. These muons are then focused in the PS and the resultant muon beam is transported through the TS towards the DS. The production solenoid presents a unique set of design challenges as the result of high radiation doses, stringent magnetic field requirements, and large structural forces. This paper describes the conceptual design of the PS cryostat and will include discussions of the vacuum vessel, thermal shield, multi-layer insulation, cooling system, cryogenic piping, and suspension system.

  7. Cloud Arcs

    Atmospheric Science Data Center

    2013-04-19

    ... causing much of the air near the centers of the arcs to rise. This air spreads out horizontally in all directions as it rises and ... is now quite weak and on meeting the undisturbed air it can rise again slightly - possibly assisting in the formation of new small cumulus ...

  8. Preliminary Design of the Vacuum System for FAIR Super FRS Quadrupole Magnet Cryostat

    NASA Astrophysics Data System (ADS)

    Akhter, J.; Pal, G.; Datta, A.; Sarma, P. R.; Bhunia, U.; Roy, S.; Bhattacharyya, S.; Nandi, C.; Mallik, C.; Bhandari, R. K.

    2012-11-01

    The Super-Conducting Fragment Separator (Super FRS) of the Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt is a large-acceptance superonducting fragment separator. The separator consists of large dipole, quadrupole and hexapole superconducting magnets. The long quadrupole magnet cryostat houses the helium chamber, which has the magnet iron and NbTi superconducting coil. The magnet weighs about 30 tons. The helium chamber is enclosed in vacuum inside the magnet cryostat. Multilayer Insulation (MLI) will be wrapped around the thermal shield to reduce radiation loss. Polyster of MLI comprises the major component responsible for outgassing. In order to reduce outgassing, pumping at elevated temperatures has to be carried out. In view of the large size and weight of the magnet, a seal off approach might not be operationally feasible. Continuous pumping of the cryostat has also been examined. Pump has been kept at a distance from the magnet considering the effect of stray magnetic fields. Oil free turbo molecular pump and scroll pump combination will be used to pump down the cryostat. The ultimate heat load of the cryostat will be highly dependent on the pressure attained. Radiation and conduction plays an important role in the heat transfer at low temperatures. This paper presents the vacuum design of the long quadrupole magnet cryostat and estimates the heat load of the cryostat.

  9. Reduction of helium loss from a superconducting accelerating cavity during initial cool-down and cryostat exchange by pre-cooling the re-condensing cryostat

    NASA Astrophysics Data System (ADS)

    O'Rourke, B. E.; Minehara, E. J.; Hayashizaki, N.; Oshima, N.; Suzuki, R.

    2015-03-01

    A Zero-Boil-Off (ZBO) cryostat is designed to realize a compact, stand-alone cryogenic system for the AIST superconducting accelerator (SCA). Under normal operation there is no evaporative helium loss from the cryomodule and therefore operating costs associated with the supply of liquid helium can be eliminated. The only significant loss of helium from the module occurs during the initial cavity cool-down procedure or when the re-condensing cryostat is replaced. It takes about 3 h to cool down the cryostat head from room temperature (300 K) to 4 K. During this time around 100 L of liquid helium is lost due to evaporation. By pre-cooling the cryostat inside a low heat load vacuum tube before transfer to the cryomodule, this evaporative loss could be essentially eliminated, significantly reducing the volume of liquid helium required for the initial cryomodule cool-down. The pre-cooling system also provides an efficient method to test the cryostat prior to use.

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

    PubMed

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

    2015-05-01

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

  11. D0 CC Cryostat Test Cooldown - Cooldown Time

    SciTech Connect

    Fuerst, J.D.; /Fermilab

    1987-08-19

    The D0 CC Cryostat is to be cold tested with LN{sub 2}. Calculations show that the time required for the 12.5 ton stainless steel inner vessel to reach equilibrium is around 5 hours if the vessel is cooled by introducing liquid into a nozzle at the bottom. The heat transfer calculations contain many assumptions. As a result, the vessel will be cooled by spraying LN{sub 2} through a nozzle at the vessel top, providing as fast a cooldown as desired. Although calculations of the bottom-fill cooldown method indicate a reasonable cooldown time, the assumption of uniform gas temperature (absence of stratification) is vital to the analysis and in fast may not be valid. Initially, as liquid is introduced into the bottom of the vessel, it will boil rapidly creating large amounts of cold gas which then cool the walls above. As the vessel bottom cools and LN{sub 2} begins to pool, however, the boiloff rate could decrease significantly. Thus the cold gas assumed in the free convection calculations is not generated. For this reason and in the interest of a speedy cooldown it has been decided to fill the vessel by spraying LN{sub 2} in through a nozzle in the vessel top.

  12. Construction and Testing of a Low-power Cryostat for MARS

    SciTech Connect

    Aalseth, Craig E.; Caggiano, Joseph A.; Day, Anthony R.; Fast, James E.; Fuller, Erin S.

    2007-10-01

    A low-power cryostat was designed and built for the Multi-sensor Airborne Radiation Survey (MARS) project for the purpose of housing a close-packed high-purity germanium (HPGe) detector array of 14 HPGe detectors. The power consumption of the cold mass in the cryostat was measured to be 4.07(11) watts, sufficient for 5.5 days of continuous operation using only 8 liters of liquid nitrogen. Temperatures throughout the cryostat were measured by platinum resistance temperature detectors. These measurements were used to determine the emissivity of the copper used in the floating radiation shield and outer cryostat wall, which was constructed using chemically cleaned and passivated copper metal. Using a PNNL-developed passivation process, an emissivity of 2.5(3)% was achieved for copper.

  13. Use of circumferential tangential cryostat sections of the intestine in the diagnosis of Hirschsprung's disease

    PubMed Central

    Emery, John L.; Finch, Ethel; Lister, James

    1967-01-01

    Technical and staining methods are described for making tangential sections using a specially prepared chuck surface in a cryostat. The method gives a rapid definitive diagnosis of Hirschsprung's disease in children. Images PMID:4177091

  14. A 3He Cryostat for Scientific Measurements in Pulsed High Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Wang, Shaoliang; Li, Liang; Liu, Mengyu; Zuo, Huakun; Peng, Tao

    A top loading 3He cryostat has been developed for scientific experiments with a 60 T pulsed magnetic field facility at Wuhan National High Magnetic Field Center. The cryostat consists of a 4He bath cryostat, a 3He insert and a closed circulation system for 3He gas handling. To eliminate the eddy current heating during the pulse, the tail of the 3He insert with a vacuum space at the bottom is made from fiberglass tubing coated with epoxy. The 3He bath is separated from the 4He bath with the vacuum space. The 4He bath cryostat provides cooling power to condense 3He gas by a neck tube on top of the tail. Experimental results have shown that the sample can be cooled down to 385 mK and kept cold for more than 150 second by one-shot cooling, which is sufficiently long for an experiment in a pulsed high magnetic field.

  15. Deep Cryogenic Low Power 24 Bits Analog to Digital Converter with Active Reverse Cryostat

    DOE PAGESBeta

    Turqueti, Marcos; Prestemon, Soren; Albright, Robert

    2015-07-15

    LBNL is developing an innovative data acquisition module for superconductive magnets where the front-end electronics and digitizer resides inside the cryostat. This electronic package allows conventional electronic technologies such as enhanced metal–oxide–semiconductor to work inside cryostats at temperatures as low as 4.2 K. This is achieved by careful management of heat inside the module that keeps the electronic envelop at approximately 85 K. This approach avoids all the difficulties that arise from changes in carrier mobility that occur in semiconductors at deep cryogenic temperatures. There are several advantages in utilizing this system. A significant reduction in electrical noise from signalsmore » captured inside the cryostat occurs due to the low temperature that the electronics is immersed in, reducing the thermal noise. The shorter distance that signals are transmitted before digitalization reduces pickup and cross-talk between channels. This improved performance in signal-to-noise rate by itself is a significant advantage. Another important advantage is the simplification of the feedthrough interface on the cryostat head. Data coming out of the cryostat is digital and serial, dramatically reducing the number of lines going through the cryostat feedthrough interface. It is important to notice that all lines coming out of the cryostat are digital and low voltage, reducing the possibility of electric breakdown inside the cryostat. This paper will explain in details the architecture and inner workings of this data acquisition system. It will also provide the performance of the analog to digital converter when the system is immersed in liquid helium, and in liquid nitrogen. Parameters such as power dissipation, integral non-linearity, effective number of bits, signal-to-noise and distortion, will be presented for both temperatures.« less

  16. Deep Cryogenic Low Power 24 Bits Analog to Digital Converter with Active Reverse Cryostat

    NASA Astrophysics Data System (ADS)

    Turqueti, Marcos; Prestemon, Soren; Albright, Robert

    LBNL is developing an innovative data acquisition module for superconductive magnets where the front-end electronics and digitizer resides inside the cryostat. This electronic package allows conventional electronic technologies such as enhanced metal-oxide-semiconductor to work inside cryostats at temperatures as low as 4.2 K. This is achieved by careful management of heat inside the module that keeps the electronic envelop at approximately 85 K. This approach avoids all the difficulties that arise from changes in carrier mobility that occur in semiconductors at deep cryogenic temperatures. There are several advantages in utilizing this system. A significant reduction in electrical noise from signals captured inside the cryostat occurs due to the low temperature that the electronics is immersed in, reducing the thermal noise. The shorter distance that signals are transmitted before digitalization reduces pickup and cross-talk between channels. This improved performance in signal-to-noise rate by itself is a significant advantage. Another important advantage is the simplification of the feedthrough interface on the cryostat head. Data coming out of the cryostat is digital and serial, dramatically reducing the number of lines going through the cryostat feedthrough interface. It is important to notice that all lines coming out of the cryostat are digital and low voltage, reducing the possibility of electric breakdown inside the cryostat. This paper will explain in details the architecture and inner workings of this data acquisition system. It will also provide the performance of the analog to digital converter when the system is immersed in liquid helium, and in liquid nitrogen. Parameters such as power dissipation, integral non-linearity, effective number of bits, signal-to-noise and distortion, will be presented for both temperatures.

  17. Model SSC (Superconducting Super Collider) dipole magnet cryostat assembly at Fermilab

    SciTech Connect

    Niemann, R.C.

    1989-03-01

    The Superconducting Super Collider (SSC) magnet development program includes the design, fabrication and testing of full length model dipole magnets. A result of the program has been the development of a magnet cryostat design. The cryostat subsystems consist of cold mass connection-slide, suspension, thermal shields, insulation, vacuum vessel and interconnections. Design details are presented along with model magnet production experience. 6 refs., 13 figs.

  18. Deep Cryogenic Low Power 24 Bits Analog to Digital Converter with Active Reverse Cryostat

    SciTech Connect

    Turqueti, Marcos; Prestemon, Soren; Albright, Robert

    2015-07-15

    LBNL is developing an innovative data acquisition module for superconductive magnets where the front-end electronics and digitizer resides inside the cryostat. This electronic package allows conventional electronic technologies such as enhanced metal–oxide–semiconductor to work inside cryostats at temperatures as low as 4.2 K. This is achieved by careful management of heat inside the module that keeps the electronic envelop at approximately 85 K. This approach avoids all the difficulties that arise from changes in carrier mobility that occur in semiconductors at deep cryogenic temperatures. There are several advantages in utilizing this system. A significant reduction in electrical noise from signals captured inside the cryostat occurs due to the low temperature that the electronics is immersed in, reducing the thermal noise. The shorter distance that signals are transmitted before digitalization reduces pickup and cross-talk between channels. This improved performance in signal-to-noise rate by itself is a significant advantage. Another important advantage is the simplification of the feedthrough interface on the cryostat head. Data coming out of the cryostat is digital and serial, dramatically reducing the number of lines going through the cryostat feedthrough interface. It is important to notice that all lines coming out of the cryostat are digital and low voltage, reducing the possibility of electric breakdown inside the cryostat. This paper will explain in details the architecture and inner workings of this data acquisition system. It will also provide the performance of the analog to digital converter when the system is immersed in liquid helium, and in liquid nitrogen. Parameters such as power dissipation, integral non-linearity, effective number of bits, signal-to-noise and distortion, will be presented for both temperatures.

  19. Performance and results of the LBNE 35 ton membrane cryostat prototype

    DOE PAGESBeta

    Montanari, David; Adamowski, Mark; Hahn, Alan; Norris, Barry; Reichenbacher, Juergen; Rucinski, Russell; Stewart, Jim; Tope, Terry

    2015-07-15

    We report on the performance and commissioning of the first membrane cryostat to be used for scientific application. The Long Baseline Neutrino Experiment (LBNE) has designed and fabricated a membrane cryostat prototype in collaboration with Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI). LBNE has designed and fabricated the supporting cryogenic system infrastructure and successfully commissioned and operated the first membrane cryostat. Original goals of the prototype are: to demonstrate the membrane cryostat technology in terms of thermal performance, feasibility for liquid argon and leak tightness; to demonstrate that we can remove all the impurities from the vessel and achieve the puritymore » requirements in a membrane cryostat without evacuation; to demonstrate that we can achieve and maintain the purity requirements of the liquid argon using mol sieve and copper filters. The purity requirements of a large liquid argon detector such as LBNE are contaminants below 200 parts per trillion (ppt) oxygen equivalent. LBNE is planning the design and construction of a large liquid argon detector. This presentation will present requirements, design and construction of the LBNE 35 ton membrane cryostat prototype, and detail the commissioning and performance. The experience and results of this prototype are extremely important for the development of the LBNE detector.« less

  20. Performance and results of the LBNE 35 ton membrane cryostat prototype

    SciTech Connect

    Montanari, David; Adamowski, Mark; Hahn, Alan; Norris, Barry; Reichenbacher, Juergen; Rucinski, Russell; Stewart, Jim; Tope, Terry

    2015-07-15

    We report on the performance and commissioning of the first membrane cryostat to be used for scientific application. The Long Baseline Neutrino Experiment (LBNE) has designed and fabricated a membrane cryostat prototype in collaboration with Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI). LBNE has designed and fabricated the supporting cryogenic system infrastructure and successfully commissioned and operated the first membrane cryostat. Original goals of the prototype are: to demonstrate the membrane cryostat technology in terms of thermal performance, feasibility for liquid argon and leak tightness; to demonstrate that we can remove all the impurities from the vessel and achieve the purity requirements in a membrane cryostat without evacuation; to demonstrate that we can achieve and maintain the purity requirements of the liquid argon using mol sieve and copper filters. The purity requirements of a large liquid argon detector such as LBNE are contaminants below 200 parts per trillion (ppt) oxygen equivalent. LBNE is planning the design and construction of a large liquid argon detector. This presentation will present requirements, design and construction of the LBNE 35 ton membrane cryostat prototype, and detail the commissioning and performance. The experience and results of this prototype are extremely important for the development of the LBNE detector.

  1. Design of the fill/transfer station cryostat for the OMEGA cryogenic target system

    SciTech Connect

    Gibson, C.R.; Charmin, C.M.; Del Bene, J.V.; Hoffmann, E.H.; Besenbruch, G.E.; Anteby, I.

    1997-09-01

    General Atomics is designing, testing and fabricating a system for supplying cryogenic targets for the University of Rochester`s OMEGA laser system. A prototype system has demonstrated the filling of 1 mm diameter, 3 {micro}m wall plastic spheres to 111 MPa (1,100 atm) with deuterium and then cooling to 18 K to condense the fuel. The production design must be capable of routinely filling and cooling targets with a 50/50 mix of deuterium and tritium and transferring them to a device which places the targets into the focus of 60 laser beams. This paper discusses the design and analysis of the production Fill/Transfer Station cryostat. The cryostat has two major components, a fixed base and a removable dome. The joint between the base and the dome is similar to a bayonet fitting and is sealed by a room temperature elastomeric o-ring. Since the cryostat must be housed in a glovebox, its design is driven strongly by maintenance requirements. To reach the equipment inside the cryostat, the dome is simply unbolted and lifted. The inside of the cryostat is maintained at 16 K by a closed loop helium flow system. Gaseous helium at about 1.4 MPa (200 psi) flows through tubes which are brazed to the inner walls. Cooling is provided by several cryocoolers which are located external to the cryostat. Liquid nitrogen is used as a heat intercept and to precool the helium gas.

  2. SSC 50mm collider dipole cryostat single tube support post conceptual design and analysis

    SciTech Connect

    Nicol, T.

    1991-08-01

    Superconducting Super Collider (SSC) dipole magnet cold masses are connected to the cryostat vacuum vessel at five places equally spaced along their length. Five supports limit sag of the cold assembly due to its own weight to a level consistent with the final magnet alignment specifications. The supports currently used in the 50mm dipoles being built at Fermilab and Brookhaven are adaptations of the design developed during the 40mm design program at Fermilab. The design essentially consists of two composite tubes nested within each other as a means of maximizing the thermal path length. In addition it provides an ideal way to utilize materials best suited for the temperature range over which they must operate. Filament would S-glass is used between 300K and 80K. Filament would graphite fiber is used between 80K and 20K and between 20K and 4.5K. S-glass is a better thermal performer above approximately 40 K. Graphite composites are ideally suited for operation below 40K.

  3. Performance of thermal shields of LHD cryostat cooled by gaseous helium with parallel paths

    NASA Astrophysics Data System (ADS)

    Imagawa, S.; Tamura, H.; Yanagi, N.; Sekiguchi, H.; Mito, T.; Satow, T.

    2002-05-01

    The Large Helical Device is the largest cryogenic apparatus for a research of fusion plasma. Thermal shields are installed to reduce heat loads to the superconducting coils. Since the total area is very wide, seamless pipes were adopted to reduce the possibility of helium leakage, and parallel cooling path is indispensable to reduce the pressure drop. Temperature differences between parallel paths will be enlarged with the procedure of cool-down, but the final temperature should be determined uniquely by each heat load in the case of gaseous helium. The number of parallel paths of the thermal shields for the plasma vacuum vessel and the cryostat vessel are set to 20 and 10, respectively, to form the periodic symmetry. The pipes were attached on the segmented plates of SUS316 by metal cleats mechanically and by high conductive epoxy resin thermally. The maximum temperature difference between the outlets of the paths was enlarged with the procedure of cool-down, but it was saturated within 40% of the average temperature rise. This difference is allowable in this system, and the temperature differences are coincide the difference of area due to the irregular shape.

  4. Study of the influence of filler wire carbon and residual element content on the mechanical properties of mechanized gas-metal-arc-welds: Final report

    SciTech Connect

    Not Available

    1988-06-01

    The individual and interactive roles of carbon, oxygen, and nitrogen and residual or tramp elements such as titanium, chromium, copper, sulfur, phosphorus, aluminum, arsenic, tin, and antimony on weld metal mechanical properties in pipeline steels are poorly documented. Further, most of the research has been done with the submerged-arc process. Systematic studies of the microstructures and toughnesses of GMAW welds are limited. A better understanding of the effects of carbon and the residual elements on weld metal toughnesses is needed so that appropriate filler wires can be produced. Accordingly, the objective of this research program was to attempt to determine the reason for the variable toughness of mechanized gas-metal-arc (GMA) girth welds and to identify means of improving toughness levels, particularly CTOD test values. This report is available from the American Gas Association Order Processing Department, 1515 Wilson Boulevard, Arlington, VA 2209-2470 (703/841-8558). 5 refs., 36 figs., 9 tabs.

  5. Vacuum Gas Tungsten Arc Welding

    NASA Technical Reports Server (NTRS)

    Weeks, J. L.; Todd, D. T.; Wooten, J. R.

    1997-01-01

    A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

  6. Design and Test of the CC Cryostat Head Cart

    SciTech Connect

    Jaques, Al; /Fermilab

    1989-08-08

    This Engineering Note documents the design of the stand to be used to transport the CC Cryostat heads into the D-Zero clean room. Due to the width of the clean room access door, the heads will have to be upright to fit through. This head cart will hold the heads upright and wheel them into the clean room on a guided track. Before the wheels are placed on the heat cart, it will be used as a stand to place the heads on for the purpose of test fitting the super insulation. The head cart will not only be structurally sufficient to support the weight of the heads but also stiff enough to allow a maximum deflection of 1/2-inch at the end of the 48-inch cylinder. The heaviest head assembly weighs about 9000 pounds. Following A.I.S.C. specifications and using a 9000 pound design load, the head cart was initially designed and built and later modified in order to meet the deflection requirements. Bending and tension stresses were limited to two thirds the yield strength. Weld and shear stresses are limited to 0.4*Fy. The C7 X 12.25 channels, the L2.5 X 2.5 X 0.25 angles adn the 1/2-inch plate are all A36 steel. In order to validate the need for an end plate in the 48-inch cylinder, an ANSYS model was created of the cylinder itself to determine it's rigidity under a point load applied at it's outer end. Appendix D contains the results which demonstrate the rigidity of the cylinder-end plate assembly. Also included is a Frame-Mac simulation of the head cart which was used to estimate the deflection at the cylinder end. A load test was performed to 133% of the rated capacity, or 12,000 pounds. The test load was incrementally applied using a crane and hook scale. A graph of deflection vs. load is shown in Appendix E. A spreader beam was designed and built to properly test the head cart. Stress calculations for this test spreader beam are included in Appendix C.

  7. Design development for the 50mm Superconducting Super Collider dipole cryostat

    SciTech Connect

    Nicol, T.H.

    1991-03-01

    The cryostat of a Superconducting Super Collider (SSC) dipole magnet consists of all magnet components except the magnet assembly itself. It serves to support the magnet accurately and reliably within the vacuum vessel, provide all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations, and must be manufacturable at low cost. The major components of the cryostat are the vacuum vessel, thermal shields, multilayer insulation system, cryogenic piping, interconnections, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course their expected operating life. This paper describes the design of the current 50mm SSC collider dipole cryostat and includes discussions on the structural and thermal considerations involved in the development of each of the major systems. Where appropriate, comparisons will be made with the 40mm cryostat. 7 refs., 5 figs., 4 tabs.

  8. Weld arc simulator

    DOEpatents

    Burr, Melvin J.

    1990-01-30

    An arc voltage simulator for an arc welder permits the welder response to a variation in arc voltage to be standardized. The simulator uses a linear potentiometer connected to the electrode to provide a simulated arc voltage at the electrode that changes as a function of electrode position.

  9. Development of a Compact Eleven Feed Cryostat for the Patriot 12-m Antenna System

    NASA Technical Reports Server (NTRS)

    Beaudoin, Christopher; Kildal, Per-Simon; Yang, Jian; Pantaleev, Miroslav

    2010-01-01

    The Eleven antenna has constant beam width, constant phase center location, and low spillover over a decade bandwidth. Therefore, it can feed a reflector for high aperture efficiency (also called feed efficiency). It is equally important that the feed efficiency and its subefficiencies not be degraded significantly by installing the feed in a cryostat. The MIT Haystack Observatory, with guidance from Onsala Space Observatory and Chalmers University, has been working to integrate the Eleven antenna into a compact cryostat suitable for the Patriot 12-m antenna. Since the analysis of the feed efficiencies in this presentation is purely computational, we first demonstrate the validity of the computed results by comparing them to measurements. Subsequently, we analyze the dependence of the cryostat size on the feed efficiencies, and, lastly, the Patriot 12-m subreflector is incorporated into the computational model to assess the overall broadband efficiency of the antenna system.

  10. A portable cryostat for the cold transfer of polarized solid HD targets: HDice-I

    SciTech Connect

    Bass, C. D.; Bade, C.; Blecher, M.; Caracappa, A.; D'Angelo, A.; Deur, A.; Dezern, G.; Glueckler, H.; Hanretty, C.; Ho, D.; Honig, A.; Kageya, T.; Khandaker, M.; Laine, V.; Lincoln, F.; Lowry, M. M.; Mahon, J. C.; O'Connell, T.; Pap, M.; Peng, P.; Preedom, B.; Sandorfi, A. M.; Seyfarth, H.; Stroeher, H.; Thorn, C. E.; Wei, X.; Whisnant, C. S.

    2014-02-01

    We developed a device with moveable liquid nitrogen and liquid helium volumes that is capable of reaching over 2 m into the coldest regions of a cryostat or dilution refrigerator and reliably extracting or installing a target of solid, polarized hydrogen deuteride (HD). This Transfer Cryostat incorporates a cylindrical neodymium rare-earth magnet that is configured as a Halbach dipole, which is maintained at 77 K and produces a 0.1 T field around the HD target. Multiple layers provide a hermetic 77 K-shield as the device is used to maintain a target at 2 K during a transfer between cryostats. Our tests with frozen-spin HD show very little polarization loss for either H (-1±2%, relative) or D (0±3%, relative) over typical transfer periods. Multiple target transfers with this apparatus have shown an overall reliability of about 95% per transfer, which is a significant improvement over earlier versions of the device.

  11. A portable cryostat for the cold transfer of polarized solid HD targets: HDice-I

    SciTech Connect

    Bass, Christopher D.; Sandorfi, Andy M.; Bade, C.; Blecher, M.; Caracappa, A.; D'Angelo, A.; Deur, A.; Dezern, G.; Glueckler, H.; Hanretty, C.; Ho, D.; Kageya, T.; Khandaker, M.; Laine, V.; Lincoln, F.; Lowry, M. M.; Mahon, J. C.; Connell, T. O.; Peng, P.; Preedom, B.; Seyfarth, H.; Stroeher, H.; Thorn, C. E.; Wei, X.; Whisnant, C. S.

    2014-02-01

    A device has been developed with moveable liquid nitrogen and liquid helium volumes that is capable of reaching over two meters into the coldest regions of a cryostat or dilution refrigerator and reliably extracting or installing a target of solid, polarized hydrogen deuteride (HD). This Transfer Cryostat incorporates a cylindrical neodymium rare-earth magnet that is configured as a Halbach dipole, which is maintained at 77 K and produces a 0.1 T field around the HD target. Multiple layers provide a hermetic 77 K-shield as the device is used to maintain a target at 2 K during a transfer between cryostats. Tests with frozen-spin HD show negligible polarization loss for either H or D over typical transfer periods. Multiple target transfers with this apparatus have shown an overall reliability of about 95% per transfer, which is a significant improvement over earlier versions of the device.

  12. Commissioning of the 4 K Outer Cryostat for the CUORE Experiment

    NASA Astrophysics Data System (ADS)

    Ferri, E.; Alessandria, F.; Biassoni, M.; Bucci, C.; Ceruti, G.; Chiarini, A.; Clemenza, M.; Cremonesi, O.; Datskov, V.; Dossena, S.; Faverzani, M.; Franceschi, M. A.; Gaigher, R.; Gorla, P.; Guetti, M.; Ligi, C.; Napolitano, T.; Nucciotti, A.; Pelosi, A.; Perego, M.; Previtali, E.; Sisti, M.; Taffarello, L.; Terranova, F.

    2014-09-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is a 1-ton scale bolometric experiment. The CUORE detector is an array of 988 TeO crystals arranged in a cylindrical, compact, and granular structure of 19 towers. These detectors will need a base temperature lower than 10 mK in order to meet the performance specifications. To cool the CUORE detector, a large cryogen free cryostat with five pulse tubes and one custom designed high power dilution refrigerator has been designed. The three vessels that form the outer shell of the CUORE cryostat were produced in 2012 and are now assembled in the Gran Sasso National Laboratories (LNGS). We report here the detailed description of the 4 K outer cryostat for the CUORE experiment together with the results of the validation tests done at the production site in 2012 and of the first commissioning to 4 K at LNGS in 2013.

  13. CLAES cryostat on-orbit performance versus ground test predictions. [Cryogenic Limb Array Etalon Spectrometer

    NASA Technical Reports Server (NTRS)

    Bell, Greg A.; Burriesci, Larry G.; Naes, Larry G., Jr.

    1993-01-01

    The paper describes the Cryogenic Limb Array Etalon Spectrometer (CLAES) launched on September 12, 1991 aboard the NASA Goddard's Upper Atmosphere Research Satellite the purpose of which is to measure the global concentrations of stratospheric species and their temperature, as a function of altitude. Particular attention is given to the design-level thermal predictions and their correlation to the results of ground tests, and to the on-orbit performance of CLAES. Also presented are data on the cryostat's thermal performance during ground operations, at spacecraft integration and during launch preparations. The CLAES functional block diagram and the cryostat schematic diagram are included.

  14. Gas arc constriction for plasma arc welding

    NASA Technical Reports Server (NTRS)

    McGee, William F. (Inventor); Rybicki, Daniel J. (Inventor)

    1994-01-01

    A welding torch for plasma arc welding apparatus has an inert gas applied circumferentially about the arc column externally of the constricting nozzle so as to apply a constricting force on the arc after it has exited the nozzle orifice and downstream of the auxiliary shielding gas. The constricting inert gas is supplied to a plenum chamber about the body of the torch and exits through a series of circumferentially disposed orifices in an annular wall forming a closure at the forward end of the constricting gas plenum chamber. The constricting force of the circumferential gas flow about the arc concentrates and focuses the arc column into a more narrow and dense column of energy after exiting the nozzle orifice so that the arc better retains its energy density prior to contacting the workpiece.

  15. Design of a horizonal liquid helium cryostat for refrigerating a flying superconducting magnet in a wind tunnel

    NASA Technical Reports Server (NTRS)

    Wu, Y. Y.

    1982-01-01

    The design of a horizontal liquid helium cryostat for refrigerating a flying superconducting magnet in a wind tunnel is presented. The basic principles of magnetic suspension theory are described and theoretical calculations of the superconducting magnet are provided. The experimental results of the boil-off of liquid nitrogen and liquid helium in the cryostat are reported.

  16. Majorana One-Tonne Cryostat Cooling Conceptual Feasibility Study Rev 1

    SciTech Connect

    Reid, Douglas J.; Fast, James E.; Orrell, John L.; Aguayo Navarrete, Estanislao

    2011-06-27

    This report evaluates the conceptual plans for a cryostat cooling design for the MAJORANA DEMONSTRATOR (MJD) one-tonne (S4) experiment. This document is based upon previous design work and experimental results used to evaluate the current MJD thermal design. A feasibility study of a cooling system for S4 based on the MJD thermosiphon experiment is presented. The one-tonne experiment will be a scaled up version of the MJD. There will be many cryostats in the S4 experiment. In this document a cryostat with up to 19 strings of germanium crystals is analyzed. Aside from an extra outer ring of crystals, the geometry of the cryostat for S4 is very similar to that for the MJD thermosiphon experiment. The materials used in the fabrication of both of these ultra-low background experiments will be underground-electroformed copper. The current MJD uses a two-phase liquid-gas cooling system to provide constant operating temperature. This document presents a theoretical investigation of a cooling system for the S4 experiment and evaluates the heat transfer performance requirements for such a system.

  17. Design and commissioning of vertical test cryostats for XFEL superconducting cavities measurements

    SciTech Connect

    Polinski, J.; Chorowski, M.; Duda, P.; Bozhko, Y.; Petersen, B.; Schaffran, J.

    2014-01-29

    The European X-ray Free Electron Laser (XFEL), now under construction at DESY in Hamburg, will make an extensive use of 1.3 GHz superconducting cavities aimed at accelerating the electrons to the energy of 17.5 GeV. The cavities will be operated at 2 K with the use of saturated HeII. Prior to their assembly in accelerator cryomodules, the RF performance of the cavities will be cold-tested in two dedicated vertical cryostats. Each cryostat allows a simultaneous testing of 4 cavities mounted on a dedicated insert. The cryostats are equipped with external lines allowing their supply with liquid helium and further conversion of the helium into superfluid He II. The paper describes the test stand flow scheme, the technical key elements, including a recuperative heat exchanger, and the cold commissioning. The thermodynamic analysis of the cryostat cool down and steady-state operation is given. A Second Law of Thermodynamics based theoretical model of the heat exchanger performance, and the model experimental validation, is presented.

  18. Design And Performance Analysis Of The Claes NE/CO2 Cryostat

    NASA Astrophysics Data System (ADS)

    Naes, L. G.; Horsley, W. J.; Ngai, C. S.; Read, D. C.; Nast, T. C.

    1988-04-01

    The Cryogenic Limb Array Etalon Spectrometer (CLAES)1 is one of nine instruments that will fly aboard the Upper Atmospheric Research Satellite (UARS)2 in the fall of 1991. CLAES is an earth-limb viewing instrument that requires cryogenic cooling of its focal plane (<15.0K), spectrometer (<30K), telescope (<150K), and baffles (<180K) in order to achieve the required performance sensitivity. Initially, the CLAES baseline design incorporated a single-stage solid hydrogen cryostat to perform the necessary cooling, however, after the Challenger shuttle disaster, the UARS and CLAES Project Offices investigated the feasibility of incorporating a completely inert cryogen system for CLAES. The result of this study showed that a dual stage Ne/CO2 cryostat would meet all sensor cooling requirements, provided that a significant increase in weight could be accommodated. In December '86, the Ne/CO2 design was adopted as the new cryostat baseline for CLAES. The focal plane and spectrometer are conductively cooled to the solid neon (13.2 K) while the telescope and internal baffles are cooled by the CO2 (121.8K). This paper describes the design and performance of the Ne/CO2 cryostat.

  19. New vertical cryostat for the high field superconducting magnet test station at CERN

    SciTech Connect

    Vande Craen, A.; Atieh, S.; Bajko, M.; Benda, V.; Rijk, G. de; Favre, G.; Giloux, C.; Minginette, P.; Parma, V.; Perret, P.; Pirotte, O.; Ramos, D.; Viret, P.; Hanzelka, P.

    2014-01-29

    In the framework of the R and D program for new superconducting magnets for the Large Hadron Collider accelerator upgrades, CERN is building a new vertical test station to test high field superconducting magnets of unprecedented large size. This facility will allow testing of magnets by vertical insertion in a pressurized liquid helium bath, cooled to a controlled temperature between 4.2 K and 1.9 K. The dimensions of the cryostat will allow testing magnets of up to 2.5 m in length with a maximum diameter of 1.5 m and a mass of 15 tons. To allow for a faster insertion and removal of the magnets and reducing the risk of helium leaks, all cryogenics supply lines are foreseen to remain permanently connected to the cryostat. A specifically designed 100 W heat exchanger is integrated in the cryostat helium vessel for a controlled cooling of the magnet from 4.2 K down to 1.9 K in a 3 m{sup 3} helium bath. This paper describes the cryostat and its main functions, focusing on features specifically developed for this project. The status of the construction and the plans for assembly and installation at CERN are also presented.

  20. New vertical cryostat for the high field superconducting magnet test station at CERN

    NASA Astrophysics Data System (ADS)

    Vande Craen, A.; Atieh, S.; Bajko, M.; Benda, V.; de Rijk, G.; Favre, G.; Giloux, C.; Hanzelka, P.; Minginette, P.; Parma, V.; Perret, P.; Pirotte, O.; Ramos, D.; Viret, P.

    2014-01-01

    In the framework of the R&D program for new superconducting magnets for the Large Hadron Collider accelerator upgrades, CERN is building a new vertical test station to test high field superconducting magnets of unprecedented large size. This facility will allow testing of magnets by vertical insertion in a pressurized liquid helium bath, cooled to a controlled temperature between 4.2 K and 1.9 K. The dimensions of the cryostat will allow testing magnets of up to 2.5 m in length with a maximum diameter of 1.5 m and a mass of 15 tons. To allow for a faster insertion and removal of the magnets and reducing the risk of helium leaks, all cryogenics supply lines are foreseen to remain permanently connected to the cryostat. A specifically designed 100 W heat exchanger is integrated in the cryostat helium vessel for a controlled cooling of the magnet from 4.2 K down to 1.9 K in a 3 m3 helium bath. This paper describes the cryostat and its main functions, focusing on features specifically developed for this project. The status of the construction and the plans for assembly and installation at CERN are also presented.

  1. Recondensation performance of liquid helium cryostat for a 28 GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Choi, Seyong; Lee, Byoung-Seob; Park, Jin Yong; Ok, Jung-Woo; Shin, Chang Seouk; Yoon, Jang-Hee; Won, Mi-Sook; Kim, Byoung-Chul

    2014-02-01

    Cryostat performance is essential for the stable operation of a superconducting magnet. A closed-cycle liquid helium cryostat was adopted for use for a superconducting electron cyclotron resonance (ECR) ion source by recondensing liquid helium vapor. The goal was to maintain the liquid helium filled reservoir at a constant level without transferring any liquid helium during the normal operation of the ECR ion source. To accomplish this, Gifford-McMahon (GM) refrigerators, which have two cold heads, were installed on the top of the cryostat. The cooling power of the GM cryocooler is 1.5 W at the second stage and 50 W at the first stage. Each stage was connected to the liquid helium reservoir, a radiation shield including high-Tc current lead, and related items. Before commissioning the ECR ion source, a preliminary evaluation of the recondensation performance was carried out with the magnet in partial operation. The design of the cryostat, its fabrication, and the experimental results are reported.

  2. Two low-cost, modular sub-λ test cryostats

    NASA Astrophysics Data System (ADS)

    Fuerst, J. D.; Kaluzny, J. A.

    2014-01-01

    Two general-purpose liquid helium (LHe) test cryostats have been developed in support of a major upgrade to the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The cryostats are capable of sustained operation below 1.8 K and currently support tests of prototype superconducting rf (srf) cavities for the APS Upgrade's Short Pulse X-ray (SPX) initiative. To save cost, two existing test vessels were reconditioned: one "bucket dewar" supporting bare cavity tests and one shielded vacuum vessel with an integral LHe reservoir for jacketed/dressed cavity tests. A new feedbox containing a heat exchanger and associated valves was also designed and fabricated to support either cryostat. The resulting modular design permits tests on a wide variety of srf cavities in various states of completion, minimizing cost and maximizing use of the hardware. Together with a dedicated vacuum pump, control system, and helium supply via storage dewar or cryoplant, these cryostats are vital to the srf cavity development effort within the APS Upgrade.

  3. Low-cost insulation system for cryostats eliminates need for a vacuum

    NASA Technical Reports Server (NTRS)

    Calvert, H. F.

    1964-01-01

    In order to eliminate the hazard caused by residual air trapped between the concentric shells of a cryostat, these annular spaces are pressurized with helium gas. This system is more economical than the use of powdered insulation maintained at low vacuums.

  4. Cryostat design for the Superconducting Super Collider 50mm aperture dipole magnet

    SciTech Connect

    Nicol, T.H. ); Tsavalas, Y.P. . Medical Systems)

    1990-09-01

    The cryostat of an SSC dipole magnet consists of all magnet components except the cold mass assembly. It serves to support the cold mass accurately and reliably within the vacuum vessel, provide all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations and must be manufacturable at low cost. The major components of the cryostat are the vacuum vessel, thermal shields, multilayer insulation (MLI) system, cryogenic piping, interconnections, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course their 25 year expected life. This paper describes the design of the current SSC collider dipole magnet cryostat and includes discussions on the thermal, structural, and dynamic considerations involved in the development of each of the major systems. 7 refs., 1 fig., 2 tabs.

  5. Development of a Cryostat to Characterize Nano-scale Superconducting Quantum Interference Devices

    NASA Astrophysics Data System (ADS)

    Longo, Mathew; Matheny, Matthew; Knudsen, Jasmine

    2016-03-01

    We have designed and constructed a low-noise vacuum cryostat to be used for the characterization of nano-scale superconducting quantum interference devices (SQUIDs). Such devices are very sensitive to magnetic fields and can measure changes in flux on the order of a single electron magnetic moment. As a part of the design process, we calculated the separation required between the cryogenic preamplifier and superconducting magnet, including a high-permeability magnetic shield, using a finite-element model of the apparatus. The cryostat comprises a vacuum cross at room temperature for filtered DC and shielded RF electrical connections, a thin-wall stainless steel support tube, a taper-sealed cryogenic vacuum can, and internal mechanical support and wiring for the nanoSQUID. The Dewar is modified with a room-temperature flange with a sliding seal for the cryostat. The flange supports the superconducting 3 Tesla magnet and thermometry wiring. Upon completion of the cryostat fabrication and Dewar modifications, operation of the nanoSQUIDs as transported from our collaborator's laboratory in Israel will be confirmed, as the lead forming the SQUID is sensitive to oxidation and the SQUIDs must be shipped in a vacuum container. After operation of the nanoSQUIDs is confirmed, the primary work of characterizing their high-speed properties will begin. This will include looking at the measurement of relaxation oscillations at high bandwidth in comparison to the theoretical predictions of the current model.

  6. SSC dipole log manget model cryostat design and initial production experience

    SciTech Connect

    Niemann, R.C.; Carson, J.A.; Engler, N.H.; Gonczy, J.D.; Nicol, T.H.

    1986-06-01

    The SSC dipole magnet development program includes the design and construction of full length magnet models for heat leak and magnetic measurements and for the evaluation of the performance of strings of magnets. The design of the model magnet cryostat is presented and the production experiences for the initial long magnet model, a heat leak measurement device, are related.

  7. A Cryogen-free Cryostat for Scientific Experiment in Pulsed High Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Wang, Shaoliang; Li, Liang; Zuo, Huakun; Liu, Mengyu; Peng, Tao

    Traditional cryostats for scientific experiments in pulsed high magnetic fields use liquid helium as the cooling source. To reduce the running cost and to increase the operational efficiency, a cryogen-free cryostat based on a GM cryocooler has been developed for a 60 T pulsed field measurement cell at Wuhan National High Magnetic Field Center. A double layer temperature-control insert was designed to obtain a stable temperature in the sample chamber of the cryostat. In order to eliminate the sample temperature fluctuation caused by the eddy current heating during the pulse, the inner layer is made from a fiberglass tubing with an epoxy coating. Different from the traditional cryostat, the sample and the temperature controller are not immerged in the 4He bath. Instead, they are separated by helium gas under sub-atmospheric pressure, which makes the heat transfer smoother. At the sample position, a resistance heater wound with antiparallel wires is mounted on the inner layer to heat the sample. Using the temperature-control insert, the temperature can be controlled with an accuracy of ±0.01 K in the range of 1.4 K-20 K, and ±0.05 K between 20 K and 300 K.

  8. Rotating arc spark plug

    DOEpatents

    Whealton, John H.; Tsai, Chin-Chi

    2003-05-27

    A spark plug device includes a structure for modification of an arc, the modification including arc rotation. The spark plug can be used in a combustion engine to reduce emissions and/or improve fuel economy. A method for operating a spark plug and a combustion engine having the spark plug device includes the step of modifying an arc, the modifying including rotating the arc.

  9. DC arc weld starter

    DOEpatents

    Campiotti, Richard H.; Hopwood, James E.

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  10. [Arc welder's lung].

    PubMed

    Molinari, Luciana; Alvarez, Clarisa; Semeniuk, Guillermo B

    2010-01-01

    Pneumoconiosis of electric arc welder or siderotic pneumoconiosis was described by Doig and McLaughlin in 1936 as a lung disease caused by chronic inhalation of iron fumes in electric arc welders. We present a case report of electric arc welder siderosis associated with high levels of ferritin, without findings of iron deposit in any other organ. PMID:21163741

  11. Arc distribution and motion during the vacuum arc remelting process as detected with a magnetostatic approach

    NASA Astrophysics Data System (ADS)

    Woodside, Rigel

    Currently, the temporal arc distribution across the ingot during the vacuum arc remelting (VAR) process is not a known or monitored parameter. It is has previously been shown that arcs can spatially constrict during VAR, and this constriction can lead to undesired defects in the material. Additionally, correct accounting for the heat flux, electric current flux, and mass flux into the ingot are critical to achieving realistic solidification models of the VAR process. An arc position measurement system capable of locating slow moving arcs and determining the arc distribution within an industrial VAR furnace was developed. The system is based on non-invasive magnetic field measurements and VAR specific forms of the magnetostatic Biot-Savart Law. Electromagnetic finite element modeling assists the analysis. The measurement system was installed on an industrial VAR furnace at the ATI facility in Albany, OR. Data were taken during the commercial production of titanium alloy. Although more arcs were present than could be resolved with the number of sensors applied, overall arc distribution shifts were detected. Arc distribution and motion during the final production of Ti-6Al-4V were examined. It is shown that several characteristic arc distribution modes can develop. This behavior was not apparent in the existing signals used to control the furnace, indicating the measurement system provides new information. Finally, a solidification model was used to assess the potential impact of the different arc distribution modes. It is shown the magnetohydrodynamic stirring patterns in the molten pool are affected, which results in localized variations in solidification times in particular at the side wall.

  12. Linear volcanic segments in the Sunda Arc, Indonesia: Implications for arc lithosphere control upon volcano distribution

    NASA Astrophysics Data System (ADS)

    Macpherson, C. G.; Pacey, A.; McCaffrey, K. J.

    2012-12-01

    The overall curvature of many subduction zones is immediately apparent and the term island arc betrays the common assumption that subduction zone magmatism occurs in curved zones. This assumption can be expressed by approximating island arcs as segments of small circles on the surface of a sphere. Such treatments predict that the location of arc volcanoes is related to their vertical separation from the slab (in fact, the depth to seismicity in the slab) and require that the primary control on the locus of magmatism lies either within the subducted slab or the mantle wedge that separates the subducted and overriding lithospheric plates. The concept of curved arcs ignores longstanding observations that magmatism in many subduction systems occurs as segments of linearly arranged volcanic centres. Further evidence for this distribution comes from the close relationship between magmatism and large scale, arc-parallel fabrics in some arcs. Similarly, exposures of deep arc crust or mantle often reveal elongation of magmatic intrusions sub-parallel to the inferred trend of the arc. The Sunda Arc forms the Indonesian islands from Sumatra to Alor and provides an important test for models of volcano distribution for several reasons. First, Sunda has hosted abundant historic volcanic activity. Second, with the notable exception of Krakatau, every volcano in the arc is subaerial from base to cone and, therefore, can be readily identified where there is a suitable extent of local mapping that can be used to ground-truth satellite imagery. Third, there are significant changes in the stress regime along the length of the arc, allowing the influence of the upper plate to be evaluated by comparison of different arc segments. Finally, much of the Sunda Arc has proved difficult to accommodate in models that try to relate volcano distribution to the depth to the subducted slab. We apply an objective line-fitting protocol; the Hough Transform, to explore the distribution of volcanoes

  13. Electrical Evaluation Of Welding Machines Based On The Arc Properties. Application To SMAW, GMAW And GTAW Processes

    NASA Astrophysics Data System (ADS)

    Miguel, V.; Martínez, A.; Manjabacas, M. C.; Coello, J.; Calatayud, A.

    2009-11-01

    In this work, a methodology to obtain the electrical behavior of arc welding equipments is presented. The method is based on the electrical arc fundamentals and it is applied to Shielding Metal Arc Welding and to Gas Metal Arc Welding processes. For the first one, different arc points are achieved by practicing several arc lengths. For MIG process, different arc lengths are made by changing the feel wire velocity. Arc current and voltage are measured for the different arc length in both cases. Finally, a Gas Tungsten Arc Welding equipment has been used to obtain the electrical arc characteristics as a function of arc length. Different considerations about the thermal and electrical principles related to the arc behavior have been made.

  14. Numerical investigations of arc behaviour in gas metal arc welding using ANSYS CFX

    NASA Astrophysics Data System (ADS)

    Schnick, M.; Fuessel, U.; Hertel, M.; Spille-Kohoff, A.; Murphy, A. B.

    2011-06-01

    Current numerical models of gas metal arc welding (GMAW) are trying to combine magnetohydrodynamics (MHD) models of the arc and volume of fluid (VoF) models of metal transfer. They neglect vaporization and assume an argon atmosphere for the arc region, as it is common practice for models of gas tungsten arc welding. These models predict temperatures above 20 000 K and a temperature distribution similar to tungsten inert gas (TIG) arcs. However, current spectroscopic temperature measurements in GMAW arcs demonstrate much lower arc temperatures. In contrast to TIG arcs they found a central local minimum of the radial temperature distribution. The paper presents a GMAW arc model that considers metal vapour and which is in a very good agreement with experimentally observed temperatures. Furthermore, the model is able to predict the local central minimum in the radial temperature and the radial electric current density distributions for the first time. The axially symmetric model of the welding torch, the work piece, the wire and the arc (fluid domain) implements MHD as well as turbulent mixing and thermal demixing of metal vapour in argon. The mass fraction of iron vapour obtained from the simulation shows an accumulation in the arc core and another accumulation on the fringes of the arc at 2000 to 5000 K. The demixing effects lead to very low concentrations of iron between these two regions. Sensitive analyses demonstrate the influence of the transport and radiation properties of metal vapour, and the evaporation rate relative to the wire feed. Finally the model predictions are compared with the measuring results of Zielińska et al.

  15. Design and Operation of A Setup with A Camera and Adjustable Mirror to Inspect the Sense-Wire Planes of the Time Projection Chamber Inside the MicroBooNE Cryostat

    SciTech Connect

    Carls, Benjamin; Horton-Smith, Glenn; James, Catherine C.; Kubinski, Robert M.; Pordes, Stephen; Schukraft, Anne; Strauss, Thomas

    2015-08-26

    Detectors in particle physics, particularly when including cryogenic components, are often enclosed in vessels that do not provide any physical or visual access to the detectors themselves after installation. However, it can be desirable for experiments to visually investigate the inside of the vessel. The MicroBooNE cryostat hosts a TPC with sense-wire planes, which had to be inspected for damage such as breakage or sagging. This inspection was performed after the transportation of the vessel with the enclosed detector to its final location, but before filling with liquid argon. Our paper describes an approach to view the inside of the MicroBooNE cryostat with a setup of a camera and a mirror through one of its cryogenic service nozzles. The paper also describes the camera and mirror chosen for the operation, the illumination, and the mechanical structure of the setup. It explains how the system was operated and demonstrates its performance.

  16. Rethinking Recycling in Arcs

    NASA Astrophysics Data System (ADS)

    Kelemen, P.; Behn, M. D.; Jagoutz, O.

    2012-12-01

    Hacker et al EPSL 2011 and Behn et al Nature Geosci 2011 investigated pathways for return of buoyant, subducted material to arc crust. These include (1) diapirs rising into the hot mantle wedge, with extensive melts adding a component to arc magmas, (2) flow of material back up a relatively cold "subduction channel", adding solids to the lower crust and small-degree partial melts to the upper crust, (3) flow from the forearc along the base of arc crust, and (4) imbrication of forearc material into arc crust. These processes add felsic, incompatible-element-rich components to arc crust. The flux of incompatible elements such as Th in arc lavas, thought to be mainly recycled from subducted sediments, is > sediment subduction flux. There are large uncertainties: arc crustal growth rates are imprecise; young, primitive arc lavas may not be representative of magmatic flux into arc crust; sediment subduction flux may have varied. Nevertheless, this result is found for all arcs examined, using recently published growth rates. Perhaps arc growth rates that include subduction erosion are systematically overestimated. Instead or in addition, maybe significant Th comes from material other than sediments. Here, we consider the implications of pathways 1-4 for arc growth rates and incompatible element enrichment, in the context of subduction erosion and arc-arc collision. Subducting arc lithologies can become separated, with only felsic components returned to arc crust. Buoyant lithologies are mobile in viscous instabilities at > 700-800°C. Whereas thin layers such as sediments may become mobile all at once, instabilities may periodically strip the hottest parts from the top of thick buoyant layers, replacing them with hot mantle. In arc-arc collision, the top of a subducting plate starts at about 0°C on the seafloor, so heating is slow. In subduction erosion, forearc material in the subducting package can be > 200°C before erosion so buoyant lithologies reach 700-800

  17. Arc initiation in cathodic arc plasma sources

    DOEpatents

    Anders, Andre

    2002-01-01

    A "triggerless" arc initiation method and apparatus is based on simply switching the arc supply voltage to the electrodes (anode and cathode). Neither a mechanical trigger electrode nor a high voltage flashover from a trigger electrode is required. A conducting path between the anode and cathode is provided, which allows a hot spot to form at a location where the path connects to the cathode. While the conductive path is eroded by the cathode spot action, plasma deposition ensures the ongoing repair of the conducting path. Arc initiation is achieved by simply applying the relatively low voltage of the arc power supply, e.g. 500 V-1 kV, with the insulator between the anode and cathode coated with a conducting layer and the current at the layer-cathode interface concentrated at one or a few contact points. The local power density at these contact points is sufficient for plasma production and thus arc initiation. A conductive surface layer, such as graphite or the material being deposited, is formed on the surface of the insulator which separates the cathode from the anode. The mechanism of plasma production (and arc initiation) is based on explosive destruction of the layer-cathode interface caused by joule heating. The current flow between the thin insulator coating and cathode occurs at only a few contact points so the current density is high.

  18. Monitoring ARC services with GangliARC

    NASA Astrophysics Data System (ADS)

    Cameron, D.; Karpenko, D.

    2012-12-01

    Monitoring of Grid services is essential to provide a smooth experience for users and provide fast and easy to understand diagnostics for administrators running the services. GangliARC makes use of the widely-used Ganglia monitoring tool to present web-based graphical metrics of the ARC computing element. These include statistics of running and finished jobs, data transfer metrics, as well as showing the availability of the computing element and hardware information such as free disk space left in the ARC cache. Ganglia presents metrics as graphs of the value of the metric over time and shows an easily-digestable summary of how the system is performing, and enables quick and easy diagnosis of common problems. This paper describes how GangliARC works and shows numerous examples of how the generated data can quickly be used by an administrator to investigate problems. It also presents possibilities of combining GangliARC with other commonly-used monitoring tools such as Nagios to easily integrate ARC monitoring into the regular monitoring infrastructure of any site or computing centre.

  19. A simplified generic cryostat thermal model for predicting cryogen mass and lifetime. [of cryogenic space telescopes

    NASA Technical Reports Server (NTRS)

    Birur, G. C.; Tsuyuki, G. T.

    1992-01-01

    This study presents a simple generic cryostat thermal model developed for predicting cryogen mass and the lifetime of cryogenic space telescopes. The model is based on a lumped parameter representation of eight nodes and over 35 conductors. The major telescope Dewar components represented as nodes are the main cryogen tank, the three vapor-cooled shields, the outer shell, barrel baffle, and the barrel baffle heat exchanger. The input to the model consists of the vapor-cooled shield, support straps and instrument cable geometry, and the cryostat heat loads from the instrument and through the aperture. The predictions from the model were compared with those from the more detailed models of IRAS, COBE, and SIRTF. Correlation of the helium flow rates of the IRAS and COBE Dewars was 12 percent above the actual flight or ground test data and for SIRTF it was less than 2 percent of the prediction from the detailed model.

  20. Characterisation of a cryostat using simultaneous, single-beam multiple-surface laser vibrometry

    NASA Astrophysics Data System (ADS)

    Kissinger, Thomas; Charrett, Thomas O. H.; James, Stephen W.; Adams, Alvin; Twin, Andrew; Tatam, Ralph P.

    2016-06-01

    A novel range-resolved interferometric signal processing technique that uses sinusoidal optical frequency modulation is applied to multi-surface vibrometry, demonstrating simultaneous optical measurements of vibrations on two surfaces using a single, collimated laser beam, with a minimum permissible distance of 3.5 cm between surfaces. The current system, using a cost-effective laser diode and a fibre-coupled, downlead insensitive setup, allows an interferometric fringe rate of up to 180 kHz to be resolved with typical displacement noise levels of 8 pm . Hz-0 5. In this paper, the system is applied to vibrometry measurements of a table-top cryostat, with concurrent measurements of the optical widow and the sample holder target inside. This allows the separation of common-mode vibrations of the whole cryostat from differential vibrations between the window and the target, allowing any resonances to be identified.

  1. The CUORE Cryostat: A 1-Ton Scale Setup for Bolometric Detectors

    NASA Astrophysics Data System (ADS)

    Ligi, C.; Alduino, C.; Alessandria, F.; Biassoni, M.; Bucci, C.; Caminata, A.; Canonica, L.; Cappelli, L.; Chott, N. I.; Copello, S.; D'Addabbo, A.; Dell'Oro, S.; Drobizhev, A.; Franceschi, M. A.; Gladstone, L.; Gorla, P.; Napolitano, T.; Nucciotti, A.; Orlandi, D.; Ouellet, J.; Pagliarone, C.; Pattavina, L.; Rusconi, C.; Santone, D.; Singh, V.; Taffarello, L.; Terranova, F.; Uttaro, S.

    2015-12-01

    The cryogenic underground observatory for rare events (CUORE) is a 1-ton scale bolometric experiment whose detector consists of an array of 988 TeO_2 crystals arranged in a cylindrical compact structure of 19 towers. This will be the largest bolometric mass ever operated. The experiment will work at a temperature around or below 10 mK. CUORE cryostat consists of a cryogen-free system based on pulse tubes and a custom high power dilution refrigerator, designed to match these specifications. The cryostat has been commissioned in 2014 at the Gran Sasso National Laboratories and reached a record temperature of 6 mK on a cubic meter scale. In this paper, we present results of CUORE commissioning runs. Details on the thermal characteristics and cryogenic performances of the system will be also given.

  2. The CUORE Cryostat: A 1-Ton Scale Setup for Bolometric Detectors

    NASA Astrophysics Data System (ADS)

    Ligi, C.; Alduino, C.; Alessandria, F.; Biassoni, M.; Bucci, C.; Caminata, A.; Canonica, L.; Cappelli, L.; Chott, N. I.; Copello, S.; D'Addabbo, A.; Dell'Oro, S.; Drobizhev, A.; Franceschi, M. A.; Gladstone, L.; Gorla, P.; Napolitano, T.; Nucciotti, A.; Orlandi, D.; Ouellet, J.; Pagliarone, C.; Pattavina, L.; Rusconi, C.; Santone, D.; Singh, V.; Taffarello, L.; Terranova, F.; Uttaro, S.

    2016-08-01

    The cryogenic underground observatory for rare events (CUORE) is a 1-ton scale bolometric experiment whose detector consists of an array of 988 TeO_2 crystals arranged in a cylindrical compact structure of 19 towers. This will be the largest bolometric mass ever operated. The experiment will work at a temperature around or below 10 mK. CUORE cryostat consists of a cryogen-free system based on pulse tubes and a custom high power dilution refrigerator, designed to match these specifications. The cryostat has been commissioned in 2014 at the Gran Sasso National Laboratories and reached a record temperature of 6 mK on a cubic meter scale. In this paper, we present results of CUORE commissioning runs. Details on the thermal characteristics and cryogenic performances of the system will be also given.

  3. Ultrasound in arc welding: a review.

    PubMed

    da Cunha, Tiago Vieira; Bohórquez, Carlos Enrique Niño

    2015-02-01

    During the last decade, the introduction of ultrasound techniques in arc welding with the intention of improving the operational performance and technical characteristics of the welding processes have been studied intensively. In this work is presented a broad review of the literature surrounding the utilization of this technique. Firstly, we discuss the use of traditional mechanical transducers to generate ultrasound in arc welding. Furthermore, we describe the various methods and their application in arc-welding processes. After, is presented a recent method of introducing ultrasonic energy in arc welding, which forms a potential alternative to the use of traditional mechanical type transducers. This method was originally developed in the late 1990s and is called arc with ultrasonic excitation of current. Here, the arc acts not only as a thermal source but also as an emission mechanism for ultrasound, acting directly on the weld pool. We presented and discussed various innovative concepts based on this method, which allows the introduction of ultrasonic energy in the arc welding without the need of any auxiliary device of welding. In addition, we also presented the variations of this method reported in the literature. Finally, we have described the respective effects attributed to the use of this method in the welding of different materials using various welding processes. PMID:25455190

  4. Design of a horizontal test cryostat for superconducting RF cavities for the FREIA facility at Uppsala University

    SciTech Connect

    Chevalier, N. R.; Thermeau, J.-P.; Bujard, P.; Junquera, T.; Hermansson, L.; Kern, R. Santiago; Ruber, R.

    2014-01-29

    Uppsala University is constructing a large scale facility, called FREIA (Facility for Research Instrumentation and Accelerator Development). FREIA includes a helium liquefier and an accelerator test facility and has the capacity to test superconducting radio-frequency (RF) cavities with the same RF system and RF power level as in an accelerator. A central element of FREIA is a horizontal test cryostat connected in closed loop to a helium liquefier. This cryostat can house two fully equipped (tuners, piezo, power coupler, helium tank) superconducting cavities to perform full RF high power tests and operate at temperatures between 1.8 K and 4.2 K. The cryostat is designed to accommodate a large array of superconducting cavities and magnets, among which the European Spallation Source (ESS) type spoke and high-β elliptical cavities as well as TESLA/ILC type elliptical cavities. The present status of the project and the design of the cryostat are reported.

  5. Long arc stabilities with various arc gas flow rates

    NASA Astrophysics Data System (ADS)

    Maruyama, K.; Takeda, K.; Sugimoto, M.; Noguchi, Y.

    2014-11-01

    A new arc torch for use in magnetically driven arc device was developed with a commercially available TIG welding arc torch. The torch has a water-cooling system to the torch nozzle and has a nozzle nut to supply a swirling-free plasma gas flow. Its endurance against arc thermal load is examined. Features of its generated arc are investigated.

  6. Making and breaking an Island arc: a new perspective from the Oligocene Kyushu-Palau arc

    NASA Astrophysics Data System (ADS)

    Ishizuka, O.; Taylor, R. N.; Yuasa, M.; Ohara, Y.

    2010-12-01

    The Kyushu-Palau Ridge (KPR) is a 2000km long remnant island arc that is separated from the active Izu-Bonin-Mariana (IBM) arc system by a series of spreading and rift basins. In this study we present 40Ar/39Ar ages and geochemical data for new samples taken from the entire length of the Kyushu-Palau arc. As such, this data provides the first comprehensive evaluation of temporal and spatial changes that are present in an Eocene-Oligocene island arc. Kyushu-Palau arc geochemistry is evaluated alongside new data from the conjugate arc which is stranded within the IBM fore-arc. Boninitic magmatism gave way to transitional arc suites including high-Mg andesites at c. 45 Ma (Ishizuka et al., 2006). After the transitional 45-41 Ma period, a mature arc system developed through the Eocene-Oligocene time: This volcanism is now preserved as the KPR. Dating results from 33 sites indicate that the KPR was active between 25 and 43 Ma, but the majority of the exposed volcanism occurred in the final phase of this arc, between 25 and 27 Ma. Unlike the IBM, the KPR has only limited systematic along-arc trends and does not include any of the strongly HIMU lavas found to the south of Izu-Bonin. Two components found along the KPR are found to have geochemistry that suggests an origin in the supra-subduction mantle rather than from the descending ocean crust. Firstly, in the south of the arc, EM-2-like lavas are present where the West Philippine Basin was in the final stages of spreading. Secondly, EM-1-like lavas are present in a restricted section of the arc, suggesting a localised heterogeneity. Subduction flux beneath the KPR generally imparted a Pb isotope vector towards low Δ8/4 (<15) and moderate 206Pb/204Pb (>19). This is a similar trend to the Eocene/Oligocene lavas found on the eastern side of the basins which split the arc at 25Ma. Another geochemical heterogeneity is found at the KPR-Daito Ridge intersection where arc magmatism occurred on pre-existing Daito Ridge crust: a

  7. The cryostat for the GRAVITY beam combiner instrument at the VLTI

    NASA Astrophysics Data System (ADS)

    Haug, M.; Haussmann, F.; Kellner, S.; Hofmann, R.; Eder, J.; Eisenhauer, F.; Lizon, J.-L.; Thummes, G.; Weisz, H.

    2012-07-01

    GRAVITY is a second generation VLTI instrument for high-precision narrow-angle astrometry and phase-referenced interferometric imaging in the astronomical K-band. The cryostat of the beam combiner instrument provides the required temperatures for the various subunits ranging from 40K to 290K with a milli-Kelvin temperature stability for some selected units. The bath cryostat is cooled with liquid nitrogen and makes use of the exhaust gas to cool the main optical bench to an intermediate temperature of 240K. The fringe tracking detector will be cooled separately by a single-stage pulse tube cooler to a temperature of 40K. The pulse tube cooler is optimized for minimum vibrations. In particular its warm side is connected to the 80K reservoir of the LN2 cryostat to minimize the required input power. All temperature levels are actively stabilized by electric heaters. The cold bench is supported separately from the vacuum vessel and the liquid nitrogen reservoir to minimize the transfer of acoustic noise onto the instrument.

  8. Operating parameters of liquid helium transfer lines used with continuous flow cryostats at low sample temperatures

    NASA Astrophysics Data System (ADS)

    Dittmar, N.; Welker, D.; Haberstroh, Ch; Hesse, U.; Krzyzowski, M.

    2015-12-01

    Continuous flow cryostats are used to cool samples to a variable temperature level by evaporating a cryogen, e.g. liquid helium (LHe). For this purpose LHe is usually stored outside the cryostat in a mobile dewar and supplied through a transfer line. In general, the complete setup has to be characterised by the lowest possible consumption of LHe. Additionally, a minimum sample temperature can be favourable from an experimental point of view. The achievement of both requirements is determined by the respective cryostat design as well as by the transfer line. In the presented work operating data, e.g. the LHe consumption during cooldown and steady state, the minimum sample temperature, and the outlet quality are analysed to characterise the performance of a reference transfer line. In addition, an experimental transfer line with built-in pressure sensors has been commissioned to examine the pressure drop along the transfer line, too. During the tests LHe impurities occurred which restricted a steady operation.

  9. The thermal design, characterization, and performance of the SPIDER long-duration balloon cryostat

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. E.; Ade, P. A. R.; Amiri, M.; Benton, S. J.; Bock, J. J.; Bond, J. R.; Bryan, S. A.; Chiang, H. C.; Contaldi, C. R.; Crill, B. P.; Dore, O.; Filippini, J. P.; Fraisse, A. A.; Gambrel, A.; Gandilo, N. N.; Hasselfield, M.; Halpern, M.; Hilton, G.; Holmes, W.; Hristov, V. V.; Irwin, K. D.; Jones, W. C.; Kermish, Z.; MacTavish, C. J.; Mason, P. V.; Megerian, K.; Moncelsi, L.; Montroy, T. E.; Morford, T. A.; Nagy, J. M.; Netterfield, C. B.; Rahlin, A. S.; Reintsema, C. D.; Ruhl, J. E.; Runyan, M. C.; Shariff, J. A.; Soler, J. D.; Trangsrud, A.; Tucker, C.; Tucker, R. S.; Turner, A. D.; Wiebe, D. V.; Young, E.

    2015-12-01

    We describe the SPIDER flight cryostat, which is designed to cool six millimeter-wavelength telescopes during an Antarctic long-duration balloon flight. The cryostat, one of the largest to have flown on a stratospheric payload, uses liquid 4 He to deliver cooling power to stages at 4.2 and 1.6 K. Stainless steel capillaries facilitate a high flow impedance connection between the main liquid helium tank and a smaller superfluid tank, allowing the latter to operate at 1.6 K as long as there is liquid in the 4.2 K main tank. Each telescope houses a closed cycle 3 He adsorption refrigerator that further cools the focal planes down to 300 mK. Liquid helium vapor from the main tank is routed through heat exchangers that cool radiation shields, providing negative thermal feedback. The system performed successfully during a 17 day flight in the 2014-2015 Antarctic summer. The cryostat had a total hold time of 16.8 days, with 15.9 days occurring during flight.

  10. An Optical Cryostat for Use in Microscopy Cooled by Stirling-Type Pulse Tube Cryocooler

    NASA Astrophysics Data System (ADS)

    Liubiao, Chen; Qiang, Zhou; Xiaoshuang, Zhu; Yuan, Zhou; Junjie, Wang

    The few products of an optical cryostat for use in microscopy in commercialapplications are generally cooled by liquid nitrogen, liquid helium or cryocoolers such as G-M cryocooler or G-M type pulse tube cryocooler (PTC). Sometimes it is not convenient to use G-M cryocooler or G-M type PTC because of its noise and big size; and in some places, liquid nitrogen, especially liquid helium, is not easily available. To overcome this limitation, an optical cryostat for use in microscopy cooled by a Stirling-type pulse tube cryocooler (SPTC) has been designed, built and tested. The refrigerator system SPTC is an important component of the optical cryostat; it has the advantages of compactness, high efficiency, and low vibration. For simplification and compactness, single-stage configuration with coaxial arrangement was employed in the developed SPTC. In order to lower the vibration, the separated configuration was adopted; its compressor and pulse tube are connected with a flexible connecting tube. At present, a lowest temperature of 20 K could be achieved. The temperature fluctuation can be controlled at ±10 mK by adjusting the input electric power to the compressor; and some considerations for further improvement will also be described in this paper.

  11. A closed cycle-cryostat for high-field Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Janoschka, A.; Svenconis, G.; Schünemann, V.

    2010-03-01

    A closed cycle-cryostat coupled to a Mössbauer spectrometer has been installed at the University of Kaiserslautern and is in full operation since march 2007. The setup is equipped with a low vibrating two-stage pulse tube cooler and has a cool down time of 48 h. The sample can be top loaded without the need to shut off the refrigerator. With the static helium exchange gas in the variable temperature insert the sample may be cooled down from room temperature to 50 K within several hours. Dynamic exchange gas with external supply of gaseous helium is used to cool the sample down to 2 K. The superconducting self-shielding split-coil generates a magnetic field of up to 5 Tesla and a stray field of ca. 60 mT at the outer cryostat walls. Mössbauer measurements can be performed in perpendicular or parallel field orientations. The sample holder and the Mössbauer drive are rigidly connected to the cryostat. In this way a line width of the two inner α-Fe lines of 0.32 mm/s has been currently achieved.

  12. NASA GRC and MSFC Space-Plasma Arc Testing Procedures

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.; Vayner, Boris V.; Galofaro, Joel T,; Hillard, G. Barry; Vaughn, Jason; Schneider, Todd

    2005-01-01

    . Finally, the necessity of testing will be emphasized, not to the exclusion of modeling, but as part of a complete strategy for determining when and if arcs will occur, and preventing them from occurring in space.

  13. Effect of acoustic field parameters on arc acoustic binding during ultrasonic wave-assisted arc welding.

    PubMed

    Xie, Weifeng; Fan, Chenglei; Yang, Chunli; Lin, Sanbao

    2016-03-01

    As a newly developed arc welding method, power ultrasound has been successfully introduced into arc and weld pool during ultrasonic wave-assisted arc welding process. The advanced process for molten metals can be realized by utilizing additional ultrasonic field. Under the action of the acoustic wave, the plasma arc as weld heat source is regulated and its characteristics make an obvious change. Compared with the conventional arc, the ultrasonic wave-assisted arc plasma is bound significantly and becomes brighter. To reveal the dependence of the acoustic binding force on acoustic field parameters, a two-dimensional acoustic field model for ultrasonic wave-assisted arc welding device is established. The influences of the radiator height, the central pore radius, the radiator radius, and curvature radius or depth of concave radiator surface are discussed using the boundary element method. Then the authors analyze the resonant mode by this relationship curve between acoustic radiation power and radiator height. Furthermore, the best acoustic binding ability is obtained by optimizing the geometric parameters of acoustic radiator. In addition, three concave radiator surfaces including spherical cap surface, paraboloid of revolution, and rotating single curved surface are investigated systematically. Finally, both the calculation and experiment suggest that, to obtain the best acoustic binding ability, the ultrasonic wave-assisted arc welding setup should be operated under the first resonant mode using a radiator with a spherical cap surface, a small central pore, a large section radius and an appropriate curvature radius. PMID:26558995

  14. A modified cryostat for photo-electrical characterization of porous materials in controlled atmosphere at very low gas dosage

    NASA Astrophysics Data System (ADS)

    Cultrera, Alessandro; Amato, Giampiero; Boarino, Luca; Lamberti, Carlo

    2014-08-01

    We developed an integrated system for photo-electrical characterization of materials for sensing applications in strictly controlled environment conditions. The peculiar aspect of this setup is the capability of a fine-tuned gas dosage and a fast dynamic chamber pressure control, coupled with current and voltage sensing within a modified cryostat. To illustrate the capabilities of our system we have characterised both p+-type mesoporous silicon (meso-PS) membranes and nano-crystalline mesoporous titanium dioxide (nc-TiO2) films. In particular, as a main topic is presented a well-resolved characterization of mesoporous silicon electrical conductivity changes induced by presence of ethanol. At low pore filling level adsorbate-shunted conduction is avoided, while dielectric screening effects on frozen doping centres are observable. Beside we presented observation of mesoporous titanium dioxide photo-conductivity as a function of different gas pressure reporting opposite effects of relatively low- and high-pressure regimes. High reproducibility provided by the system is discussed as a final remark.

  15. TIGER Arc Modification Application

    SciTech Connect

    Armstrong, Hillary

    1995-03-06

    The application enables the geometric correction of TIGER arcs to a more accurate spatial data set. This is done in a structured automated environment according to Census Bureau guidelines and New Mexico state GIS standards. Arcs may be deleted, added, combined, split, and moved relative to a coverage or image displayed in the background.

  16. Simplified Methodology to Estimate the Maximum Liquid Helium (LHe) Cryostat Pressure from a Vacuum Jacket Failure

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Richards, W. Lance

    2015-01-01

    The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared astronomical observation experiments. These experiments carry sensors cooled to liquid helium temperatures. The liquid helium supply is contained in large (i.e., 10 liters or more) vacuum-insulated dewars. Should the dewar vacuum insulation fail, the inrushing air will condense and freeze on the dewar wall, resulting in a large heat flux on the dewar's contents. The heat flux results in a rise in pressure and the actuation of the dewar pressure relief system. A previous NASA Engineering and Safety Center (NESC) assessment provided recommendations for the wall heat flux that would be expected from a loss of vacuum and detailed an appropriate method to use in calculating the maximum pressure that would occur in a loss of vacuum event. This method involved building a detailed supercritical helium compressible flow thermal/fluid model of the vent stack and exercising the model over the appropriate range of parameters. The experimenters designing science instruments for SOFIA are not experts in compressible supercritical flows and do not generally have access to the thermal/fluid modeling packages that are required to build detailed models of the vent stacks. Therefore, the SOFIA Program engaged the NESC to develop a simplified methodology to estimate the maximum pressure in a liquid helium dewar after the loss of vacuum insulation. The method would allow the university-based science instrument development teams to conservatively determine the cryostat's vent neck sizing during preliminary design of new SOFIA Science Instruments. This report details the development of the simplified method, the method itself, and the limits of its applicability. The simplified methodology provides an estimate of the dewar pressure after a loss of vacuum insulation that can be used for the initial design of the liquid helium dewar vent stacks. However, since it is not an exact

  17. BEC-Cryostat Interface: A Novel Platform for Hybrid Quantum Systems

    NASA Astrophysics Data System (ADS)

    Date, Aditya; Patil, Yogesh Sharad; Schwab, Keith; Vengalattore, Mukund

    2015-05-01

    We present our experimental progress towards the implementation of a unique BEC-cryostat interface. This apparatus allows for the control and manipulation of ultracold atoms in close proximity to cryogenic surfaces. Such a system enables us to realize a hybrid quantum system consisting of a BEC strongly coupled magnetically to an ultra-high Q mechanical resonator, thus enabling precise atomic sensing of mechanical motion. Furthermore, the unprecedented sensitivities afforded by our atomic system open avenues to surface studies of correlated electronic systems at cryogenic temperatures. This work is supported by the DARPA QuASAR program through a grant from the ARO.

  18. [Possibility of the morphometry of the neuronal body and nucleus in cryostat sections of nerve tissue].

    PubMed

    Krasnov, I B

    1982-02-01

    A method of fixation by the Carnoy liquid and of gallocyanine staining is proposed in order to obtain clear-cut boundaries of the neuron body, nucleus and nucleolus in cryostat sections of non-fixed frozen nerve tissue, for subsequent morphometry of the body and nucleus of nerve cells. In the resulting sections, the clearness of boundaries of the body and nucleus in a neuron is sufficient for measuring its diameter with the coefficient of variation not exceeding 2.5%. PMID:7041376

  19. RF status of superconducting module development suitable for CW operation: ELBE cryostats

    NASA Astrophysics Data System (ADS)

    Teichert, J.; Büchner, A.; Büttig, H.; Gabriel, F.; Michel, P.; Möller, K.; Lehnert, U.; Schneider, Ch.; Stephan, J.; Winter, A.

    2006-02-01

    For the ELBE electron linear accelerator a superconducting accelerating module was developed and is now in routine operation. The cryostat contains two TESLA cavities (1.3 GHz) and is designed for continuous-wave (CW) operation with an accelerating gradient of 10 MV/m and a maximum average beam current of 1 mA. For the RF power two 10 kW klystrons are used. Special tuners, power couplers, low-level RF control, cryogenic control systems and safety systems were developed. Engineering design, operation parameters and experience with the module are discussed.

  20. Welding arc initiator

    DOEpatents

    Correy, Thomas B.

    1989-01-01

    An improved inert gas shielded tungsten arc welder is disclosed of the type wherein a tungsten electrode is shielded within a flowing inert gas, and, an arc, following ignition, burns between the energized tungsten electrode and a workpiece. The improvement comprises in combination with the tungsten electrode, a starting laser focused upon the tungsten electrode which to ignite the electrode heats a spot on the energized electrode sufficient for formation of a thermionic arc. Interference problems associated with high frequency starters are thus overcome.

  1. Welding arc initiator

    DOEpatents

    Correy, T.B.

    1989-05-09

    An improved inert gas shielded tungsten arc welder is disclosed of the type wherein a tungsten electrode is shielded within a flowing inert gas, and, an arc, following ignition, burns between the energized tungsten electrode and a workpiece. The improvement comprises in combination with the tungsten electrode, a starting laser focused upon the tungsten electrode which to ignite the electrode heats a spot on the energized electrode sufficient for formation of a thermionic arc. Interference problems associated with high frequency starters are thus overcome. 3 figs.

  2. Electric arc saw apparatus

    DOEpatents

    Deichelbohrer, Paul R [Richland, WA

    1986-01-01

    A portable, hand held electric arc saw has a small frame for supporting an electrically conducting rotary blade which serves as an electrode for generating an electric arc to erode a workpiece. Electric current is supplied to the blade by biased brushes and a slip ring which are mounted in the frame. A pair of freely movable endless belts in the form of crawler treads stretched between two pulleys are used to facilitate movement of the electric arc saw. The pulleys are formed of dielectric material to electrically insulate the crawler treads from the frame.

  3. Metal halide arc discharge lamp having short arc length

    NASA Technical Reports Server (NTRS)

    Muzeroll, Martin E. (Inventor)

    1994-01-01

    A metal halide arc discharge lamp includes a sealed light-transmissive outer jacket, a light-transmissive shroud located within the outer jacket and an arc tube assembly located within the shroud. The arc tube assembly includes an arc tube, electrodes mounted within the arc tube and a fill material for supporting an arc discharge. The electrodes have a spacing such that an electric field in a range of about 60 to 95 volts per centimeter is established between the electrodes. The diameter of the arc tube and the spacing of the electrodes are selected to provide an arc having an arc diameter to arc length ratio in a range of about 1.6 to 1.8. The fill material includes mercury, sodium iodide, scandium tri-iodide and a rare gas, and may include lithium iodide. The lamp exhibits a high color rendering index, high lumen output and high color temperature.

  4. Filtered cathodic arc source

    DOEpatents

    Falabella, Steven; Sanders, David M.

    1994-01-01

    A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45.degree. to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles.

  5. Filtered cathodic arc source

    DOEpatents

    Falabella, S.; Sanders, D.M.

    1994-01-18

    A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge is described. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45[degree] to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles. 3 figures.

  6. Filtered cathodic arc source

    SciTech Connect

    Falabella, S.; Sanders, D.M.

    1992-12-31

    Disclosed is a continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45{degrees} to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles.

  7. Electric arc saw apparatus

    DOEpatents

    Deichelbohrer, P.R.

    1983-08-08

    A portable, hand-held electric arc saw apparatus comprising a small frame for supporting an electrically conducting rotary blade which serves as an electrode for generating an electric arc between the blade and a workpiece of opposite polarity. Electrically conducting means are provided on said frame for transmitting current to said blade. A pair of freely movable endless belts in the form of crawler treads are employed to facilitate movement of the apparatus relative to the workpiece.

  8. A vibration free closed-cycle 1 K cryostat with a 4 K pulse tube cryocooler

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Lichtenwalter, Ben

    2014-01-01

    A 1 K closed-cycle cryostat, pre-cooled by a 4 K pulse tube cryocooler, has been developed. The Cryomech PT410 pulse tube cryocooler liquefies helium in a vacuum insulated sleeve at a pressure of ˜1 atm. Liquid helium flows through a JT valve and into a 1 K pot that is evacuated by a vacuum pump. The discharged gas from the vacuum is routed to the top of the sleeve to be liquefied. This design accomplishes closed-cycle 1 K refrigeration and provides continuous cooling below 2 K. Using two XDS10 vacuum pumps and with the JT valve optimized for maximum cooling capacity, the 1 K cooling station can reach a no-load temperature of 1.51 K and provide a capacity of 225 mW at 1.76 K. The temperature oscillations on the 4 K and 1 K cooling stations are ± 3 mK. The cryostat is designed so that there is no direct mechanical contact between the pulse tube cryocooler heat exchangers and the 1 K cooling station. This design feature enables exceptionally low vibration operation at the 1 K cooling station.

  9. Pulse tube refrigerator cryostat with an intrinsic top-loading system

    NASA Astrophysics Data System (ADS)

    Koettig, T.; Moldenhauer, S.; Thürk, M.; Seidel, P.

    2006-06-01

    The authors have undertaken basic research and prototype developments of four-valve pulse-tube refrigerators (FVPTR) since several years. Two single-stage FVPTR in coaxial and U-shaped arrangement have been designed for maximum refrigeration power at cooling temperatures below 30 K. The heat flow through a thermal link between the pulse tube and the regenerator is the determining difference between the U-shaped and the coaxial configuration. The intrinsic heat flux has a complex influence on the cooler performance, e.g. the cooling power, the temperature distribution within the pulse tube and the dynamic losses. Based on these results we propose a design study of a coaxial FVPTR with an intrinsic top-loading system. This cryostat is most suitable for measurements and analytical applications with even low maintenance costs. The main advantage for the operator is the rapid sample exchange while the refrigerator is operating. The process takes only a matter of minutes. Thus the time to cool successive samples is greatly reduced over cold finger cryostats.

  10. A Simple Dewar/Cryostat for Thermally Equilibrating Samples at Known Temperatures for Accurate Cryogenic Luminescence Measurements.

    PubMed

    Weaver, Phoebe G; Jagow, Devin M; Portune, Cameron M; Kenney, John W

    2016-01-01

    The design and operation of a simple liquid nitrogen Dewar/cryostat apparatus based upon a small fused silica optical Dewar, a thermocouple assembly, and a CCD spectrograph are described. The experiments for which this Dewar/cryostat is designed require fast sample loading, fast sample freezing, fast alignment of the sample, accurate and stable sample temperatures, and small size and portability of the Dewar/cryostat cryogenic unit. When coupled with the fast data acquisition rates of the CCD spectrograph, this Dewar/cryostat is capable of supporting cryogenic luminescence spectroscopic measurements on luminescent samples at a series of known, stable temperatures in the 77-300 K range. A temperature-dependent study of the oxygen quenching of luminescence in a rhodium(III) transition metal complex is presented as an example of the type of investigation possible with this Dewar/cryostat. In the context of this apparatus, a stable temperature for cryogenic spectroscopy means a luminescent sample that is thermally equilibrated with either liquid nitrogen or gaseous nitrogen at a known measureable temperature that does not vary (ΔT < 0.1 K) during the short time scale (~1-10 sec) of the spectroscopic measurement by the CCD. The Dewar/cryostat works by taking advantage of the positive thermal gradient dT/dh that develops above liquid nitrogen level in the Dewar where h is the height of the sample above the liquid nitrogen level. The slow evaporation of the liquid nitrogen results in a slow increase in h over several hours and a consequent slow increase in the sample temperature T over this time period. A quickly acquired luminescence spectrum effectively catches the sample at a constant, thermally equilibrated temperature. PMID:27501355

  11. EDITORIAL Metal vapour in atmospheric-pressure arcs Metal vapour in atmospheric-pressure arcs

    NASA Astrophysics Data System (ADS)

    Murphy, Anthony B.

    2010-11-01

    determine Stark widths of spectral lines is discussed in a further contribution. Two papers address the calculation of important plasma data sets, in particular net radiative emission coefficients and diffusion coefficients, which are vital input for computational models. Four sophisticated computational modelling studies of the influence of metal vapour on gas-metal arc welding, gas-tungsten arc welding, and arc splitting in low-voltage circuit breakers are then presented. The final contribution describes the application of a multiscale computational model to investigate the important occupational health problem of the production of fume from the metal vapour produced in welding arcs. Overall, the papers presented give an overview of the state of the art of research into metal vapour in atmospheric-pressure arcs, and at the same time constitute real progress in this topical and important field.

  12. Episodicity in back-arc tectonic regimes

    NASA Astrophysics Data System (ADS)

    Clark, Stuart R.; Stegman, Dave; Müller, R. Dietmar

    2008-12-01

    The evolution of back-arc basins is tied to the development of the dynamics of the subduction system they are a part of. We present a study of back-arc basins and model their development by implementing 3D time-dependant computer models of subduction including an overriding plate. We define three types of episodicity: pseudo-, quasi- and hyper-episodicity, and find evidence of these in nature. Observations of back-arc basin ages, histories of spreading, quiescence and compression in the overriding plate give us an understanding of the time-development of these subduction zones and back-arc basins. Across the globe today, a number of trenches are advancing—the Izu-Bonin Trench, the Mariana Trench, the Japan Trench, the Java-Sunda Trench and the central portion of the Peru-Chile Trench (the Andes subduction zone). The Izu-Bonin, Mariana and Japan all have established back-arc basins, while the others have documented episodes of spreading, quiescence, compression or a combination of these. The combination of advancing and retreating trench motion places these subduction zones in the category of hyper-episodicity. Quasi-episodicity, in which the back-arc shifts between phases of rifting, spreading and quiescence, is the dominant form of episodic back-arc development in the present. We find this type of episodicity in models for which the system is dynamically consistent—that we have allowed the subducting plate's velocity to be determined by the sinking slabs' buoyancy. Quasi- and hyper-episodicity are only found in subduction zones with relatively high subducting plate velocities, between 6 and 9 cm/year. Finally, those subduction zones for which the subducting plate is moving slowly, such as in the Mediterranean or the Scotia Sea, experience only pseudo-episodicity, where the spreading moves linearly towards the trench but often does so in discrete ridge-jump events.

  13. The statistical difference between bending arcs and regular polar arcs

    NASA Astrophysics Data System (ADS)

    Kullen, A.; Fear, R. C.; Milan, S. E.; Carter, J. A.; Karlsson, T.

    2015-12-01

    In this work, the Polar UVI data set by Kullen et al. (2002) of 74 polar arcs is reinvestigated, focusing on bending arcs. Bending arcs are typically faint and form (depending on interplanetary magnetic field (IMF) By direction) on the dawnside or duskside oval with the tip of the arc splitting off the dayside oval. The tip subsequently moves into the polar cap in the antisunward direction, while the arc's nightside end remains attached to the oval, eventually becoming hook-shaped. Our investigation shows that bending arcs appear on the opposite oval side from and farther sunward than most regular polar arcs. They form during By-dominated IMF conditions: typically, the IMF clock angle increases from 60 to 90° about 20 min before the arc forms. Antisunward plasma flows from the oval into the polar cap just poleward of bending arcs are seen in Super Dual Auroral Radar Network data, indicating dayside reconnection. For regular polar arcs, recently reported characteristics are confirmed in contrast to bending arcs. This includes plasma flows along the nightside oval that originate close to the initial arc location and a significant delay in the correlation between IMF By and initial arc location. In our data set, the highest correlations are found with IMF By appearing at least 1-2 h before arc formation. In summary, bending arcs are distinctly different from regular arcs and cannot be explained by existing polar arc models. Instead, these results are consistent with the formation mechanism described in Carter et al. (2015), suggesting that bending arcs are caused by dayside reconnection.

  14. Modeling of thermal plasma arc technology FY 1994 report

    SciTech Connect

    Hawkes, G.L.; Nguyen, H.D.; Paik, S.; McKellar, M.G.

    1995-03-01

    The thermal plasma arc process is under consideration to thermally treat hazardous and radioactive waste. A computer model for the thermal plasma arc technology was designed as a tool to aid in the development and use of the plasma arc-Joule beating process. The value of this computer model is to: (a) aid in understanding the plasma arc-Joule beating process as applied to buried waste or exhumed buried waste, (b) help design melter geometry and electrode configuration, (c) calculate the process capability of vitrifying waste (i.e., tons/hour), (d) develop efficient plasma and melter operating conditions to optimize the process and/or reduce safety hazards, (e) calculate chemical reactions during treatment of waste to track chemical composition of off-gas products, and composition of final vitrified waste form and (f) help compare the designs of different plasma-arc facilities. A steady-state model of a two-dimensional axisymmetric transferred plasma arc has been developed and validated. A parametric analysis was performed that studied the effects of arc length, plasma gas composition, and input power on the temperatures and velocity profiles of the slag and plasma gas. A two-dimensional transient thermo-fluid model of the US Bureau of Mines plasma arc melter has been developed. This model includes the growth of a slag pool. The thermo-fluid model is used to predict the temperature and pressure fields within a plasma arc furnace. An analysis was performed to determine the effects of a molten metal pool on the temperature, velocity, and voltage fields within the slag. A robust and accurate model for the chemical equilibrium calculations has been selected to determine chemical composition of final waste form and off-gas based on the temperatures and pressures within the plasma-arc furnace. A chemical database has been selected. The database is based on the materials to be processed in the plasma arc furnaces.

  15. Arcing in LEO: Does the Whole Array Discharge?

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.; Vayner, Boris V.; Galofaro, Joel T.; Hillard, G. Barry

    2005-01-01

    The conventional wisdom about solar array arcing in LEO is that only the parts of the solar array that are swept over by the arc-generated plasma front are discharged in the initial arc. This limits the amount of energy that can be discharged. Recent work done at the NASA Glenn Research Center has shown that this idea is mistaken. In fact, the capacitance of the entire solar array may be discharged, which for large arrays leads to very large and possibly debilitating arcs, even if no sustained arc occurs. We present the laboratory work that conclusively demonstrates this fact by using a grounded plate that prevents the arc-plasma front from reaching certain array strings. Finally, we discuss the dependence of arc strength and arc pulse width on the capacitance that is discharged, and provide a physical mechanism for discharge of the entire array, even when parts of the array are not accessible to the arc-plasma front. Mitigation techniques are also presented.

  16. Arcing in LEO - Does the Whole Array Discharge?

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.; Vayner, Boris V.; Galofaro, Joel T.; Hillard, G. Barry

    2005-01-01

    The conventional wisdom about solar array arcing in LEO is that only the parts the solar array that are swept over by the arc-generated plasma front are discharged in the initial arc. This limits the amount of energy that can be discharged. Recent work done at the NASA Glenn Research Center has shown that this idea is mistaken. In fact, the capacitance of the entire solar array may be discharged, which for large arrays leads to very large and possibly debilitating arcs, even if no sustained arc occurs. We present the laboratory work that conclusively demonstrates this fact by using a grounded plate that prevents the arc-plasma front from reaching certain array strings. Finally, we discuss the dependence of arc strength and arc pulse width on the capacitance that is discharged, and provide a physical mechanism for discharge of the entire array, even when parts of the array are not accessible to the arc-plasma front. Mitigation techniques are also presented.

  17. ALICE—ARC integration

    NASA Astrophysics Data System (ADS)

    Anderlik, C.; Gregersen, A. R.; Kleist, J.; Peters, A.; Saiz, P.

    2008-07-01

    AliEn or Alice Environment is the Grid middleware developed and used within the ALICE collaboration for storing and processing data in a distributed manner. ARC (Advanced Resource Connector) is the Grid middleware deployed across the Nordic countries and gluing together the resources within the Nordic Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructure, using the client tools available in AliEn. The inter-operation has two aspects, one is the data management part and the second the job management aspect. The first aspect was solved by using dCache across NDGF to handle data. Therefore, we will concentrate on the second part. Solving it, was somewhat cumbersome, mainly due to the different computing models employed by AliEn and ARC. AliEN uses an Agent based pull model while ARC handles jobs through the more 'traditional' push model. The solution comes as a module implementing the functionalities necessary to achieve AliEn job submission and management to ARC enabled sites.

  18. Consolidating NASA's Arc Jets

    NASA Technical Reports Server (NTRS)

    Balboni, John A.; Gokcen, Tahir; Hui, Frank C. L.; Graube, Peter; Morrissey, Patricia; Lewis, Ronald

    2015-01-01

    The paper describes the consolidation of NASA's high powered arc-jet testing at a single location. The existing plasma arc-jet wind tunnels located at the Johnson Space Center were relocated to Ames Research Center while maintaining NASA's technical capability to ground-test thermal protection system materials under simulated atmospheric entry convective heating. The testing conditions at JSC were reproduced and successfully demonstrated at ARC through close collaboration between the two centers. New equipment was installed at Ames to provide test gases of pure nitrogen mixed with pure oxygen, and for future nitrogen-carbon dioxide mixtures. A new control system was custom designed, installed and tested. Tests demonstrated the capability of the 10 MW constricted-segmented arc heater at Ames meets the requirements of the major customer, NASA's Orion program. Solutions from an advanced computational fluid dynamics code were used to aid in characterizing the properties of the plasma stream and the surface environment on the calorimeters in the supersonic flow stream produced by the arc heater.

  19. Vacuum arc deposition devices

    SciTech Connect

    Boxman, R.L.; Zhitomirsky, V.N.

    2006-02-15

    The vacuum arc is a high-current, low-voltage electrical discharge which produces a plasma consisting of vaporized and ionized electrode material. In the most common cathodic arc deposition systems, the arc concentrates at minute cathode spots on the cathode surface and the plasma is emitted as a hypersonic jet, with some degree of contamination by molten droplets [known as macroparticles (MPs)] of the cathode material. In vacuum arc deposition systems, the location and motion of the cathode spots are confined to desired surfaces by an applied magnetic field and shields around undesired surfaces. Substrates are mounted on a holder so that they intercept some portion of the plasma jet. The substrate often provides for negative bias to control the energy of depositing ions and heating or cooling to control the substrate temperature. In some systems, a magnetic field is used to guide the plasma around an obstacle which blocks the MPs. These elements are integrated with a deposition chamber, cooling, vacuum gauges and pumps, and power supplies to produce a vacuum arc deposition system.

  20. Making and breaking an island arc: A new perspective from the Oligocene Kyushu-Palau arc, Philippine Sea

    NASA Astrophysics Data System (ADS)

    Ishizuka, Osamu; Taylor, Rex N.; Yuasa, Makoto; Ohara, Yasuhiko

    2011-05-01

    The Kyushu-Palau Ridge (KPR) is a 2600 km long remnant island arc that is separated from the active Izu-Bonin-Mariana (IBM) arc by a series of spreading and rift basins. We present 40Ar/39Ar ages and geochemical data for the entire length of the Kyushu-Palau arc as well as for the conjugate arc which is stranded within the IBM fore arc. New 40Ar/39Ar ages indicate that the KPR was active between 25 and 48 Ma, but the majority of the exposed volcanism occurred in the final phase, between 25 and 28 Ma. Rifting of the Kyushu-Palau arc to form the Shikoku and Parece Vela basins occurred simultaneously along the length of the arc (circa 25 Ma), and at a similar distance from the trench. Unlike the IBM, the KPR has only limited systematic along-arc geochemical trends. Two geochemical components within the KPR indicate an origin in the suprasubduction mantle. First, EM-1-like lavas are identified in a restricted section of the arc, suggesting a localized heterogeneity. Second, EM-2-like arc volcanoes formed on juvenile West Philippine Basin crust, potentially reflecting ingress of mantle from the then active EM-2 province which lies in the west. Another geochemical heterogeneity is found at the KPR-Daito Ridge intersection where the arc developed on preexisting Cretaceous Daito Ridge crust. The geochemical characteristics at this intersection likely result from the involvement of sub-Daito Ridge lithospheric mantle. Subduction flux beneath the KPR generally matches post-45 Ma Eocene/Oligocene lavas in the IBM fore arc, involving fluids and melts derived from altered igneous crust.

  1. Pulsed Long Arc Welding

    NASA Astrophysics Data System (ADS)

    Krampit, N. Yu

    2016-04-01

    The paper presents a method and an appliance for pulsed arc welding. The method supports dosage of energy required for melting each bead of electrode metal starting from the detachment of a bead. The appliance including a sensor to register bead detachment shows this moment due to the voltage burst in the arc space. Transferred beads of electrode metal are of similar size because of the dosage of energy used for melting each bead, as the consequence, the process is more stable and starting conditions to transfer electrode metal are similar, as the result, a produced weld is improved.

  2. Arc electrode interaction study

    NASA Technical Reports Server (NTRS)

    Zhou, X.; Berns, D.; Heberlein, J.

    1994-01-01

    The project consisted of two parts: (1) the cathode interaction studies which were a continuation of previous work and had the objective of increasing our understanding of the microscopic phenomena controlling cathode erosion in arc jet thrusters, and (2) the studies of the anode attachment in arc jet thrusters. The cathode interaction studies consisted of (1) a continuation of some modeling work in which the previously derived model for the cathode heating was applied to some specific gases and electrode materials, and (2) experimental work in which various diagnostics was applied to the cathode. The specific diagnostics used were observation of the cathode tip during arcing using a Laser Strobe Video system in conjunction with a tele-microscope, a monochromator with an optical multichannel analyzer for the determination of the cathode temperature distribution, and various ex situ materials analysis methods. The emphasis of our effort was shifted to the cathode materials analysis because a parallel project was in place during the second half of 1993 with a visiting scientist pursuing arc electrode materials studies. As a consequence, the diagnostic investigations of the arc in front of the cathode had to be postponed to the first half of 1994, and we are presently preparing these measurements. The results of last year's study showed some unexpected effects influencing the cathode erosion behavior, such as increased erosion away from the cathode tip, and our understanding of these effects should improve our ability to control cathode erosion. The arc jet anode attachment studies concentrated on diagnostics of the instabilities in subsonic anode attachment arc jet thrusters, and were supplemental measurements to work which was performed by one of the authors who spent the summer as an intern at NASA Lewis Research Center. A summary of the results obtained during the internship are included because they formed an integral part of the study. Two tasks for 1994, the

  3. Energy losses in the D0 {beta} solenoid cryostat caused by current changes

    SciTech Connect

    Visser, A.T.

    1993-11-01

    The proposed D0 {beta} solenoid is a superconducting solenoid mounted inside an aluminum tube which supports the solenoid winding over it`s full length. This aluminum support tube, also called bobbin, is therefore very tightly coupled to magnetic flux changes caused by solenoid current variations. These current changes in the solenoid, will cause answer currents to flow in the resistive bobbin wall and therefore cause heat losses. The insertion of an external dump resistor in the solenoid current loop reduces energy dissipation inside the cryostat during a quench and will shorten the discharge time constant. This note presents a simple electrical model for the coupled bobbin and solenoid and makes it easier to understand the circuit behavior and losses. Estimates for the maximum allowable rate of solenoid current changes, based on the maximum permissible rate of losses can be made using this model.

  4. Building and Testing a Superconductivity Measurement Platform for a Helium Cryostat

    NASA Astrophysics Data System (ADS)

    Rose, Heath; Ostrander, Joshua; Wu, Jim; Ramos, Roberto

    2013-03-01

    Superconductivity experiments using Josephson junctions are an excellent environment to study quantum mechanics and materials science. A standard electrical transport technique uses filtered four wire measurement of these superconducting devices. We report our experience as undergraduates in a liberal arts college in building and testing an experimental platform anchored on the cold-finger of a helium cryostat and designed for performing differential conductance measurements in Josephson junctions. To filter out RF, we design, build and test cryogenic filters using ceramic capacitors and inductors and thermocoax cables. We also use fixed attenuators for thermal anchoring and use miniature connectors to connect wires and coax to a sample box. We report on progress in our diagnostic measurements as well as low-temperature tunneling experiments to probe the structure of the energy gap in both single- and multi-gapped superconductors. We acknowledge the support of the National Science Foundation through NSF Grant DMR-1206561.

  5. Design and construction of a high temperature superconducting power cable cryostat for use in railway system applications

    NASA Astrophysics Data System (ADS)

    Tomita, M.; Muralidhar, M.; Suzuki, K.; Fukumoto, Y.; Ishihara, A.; Akasaka, T.; Kobayashi, Y.

    2013-10-01

    The primary objective of the current effort was to design and test a cryostat using a prototype five-meter long high temperature Bi2Sr2Ca2Cu3Oy (Bi-2223) superconducting dc power cable for railway systems. To satisfy the safety regulations of the Govt of Japan a mill sheet covered by super-insulation was used inside the walls of the cryostat. The thicknesses of various walls in the cryostat were obtained from a numerical analysis. A non-destructive inspection was utilized to find leaks under vacuum or pressure. The cryostat target temperature range was around 50 K, which is well below liquid nitrogen temperature, the operating temperature of the superconducting cable. The qualification testing was carried out from 77 down to 66 K. When using only the inner sheet wire, the maximum current at 77.3 K was 10 kA. The critical current (Ic) value increased with decreasing temperature and reached 11.79 kA at 73.7 K. This is the largest dc current reported in a Bi2Sr2Ca2Cu3Oy or YBa2Cu3Oy (Y-123) superconducting prototype cable so far. These results verify that the developed DC superconducting cable is reliable and fulfils all the requirements necessary for successful use in various power applications including railway systems. The key issues for the design of a reliable cryogenic system for superconducting power cables for railway systems are discussed.

  6. NOTE: Validation of optical coherence tomography in vivo using cryostat histology

    NASA Astrophysics Data System (ADS)

    Gambichler, T.; Moussa, G.; Regeniter, P.; Kasseck, C.; Hofmann, M. R.; Bechara, F. G.; Sand, M.; Altmeyer, P.; Hoffmann, K.

    2007-03-01

    We aimed to validate for the first time optical coherence tomography (OCT) measurements of epidermal thickness (ET) using cryopreparation for histology. OCT assessments of ET were performed on healthy skin using the algorithms as follows: first, peak-to-valley analysis of the A-scan (ET-OCT-V), second, line-traced image analysis of the B-scan (ET-OCT-IA). Histology was performed using cryostat sections which were also evaluated using the image analysis (ET-Histo). We selected 114 samples, including B-scans and corresponding histology, for method comparison between ET-OCT-IA and ET-Histo. Forty-two A-scans were available for method comparison between ET-OCT-V and ET-Histo. Bland and Altman plots revealed a marked bias with wide 95% limits of agreement for ET-OCT-V versus ET-Histo. Comparison of ET-OCT-IA versus ET-Histo revealed only a slight bias and narrow 95% limits of agreement. A-scan analysis for ET determination is linked to significant limitations and lacks agreement with histology. By contrast, we observed satisfactory agreement between ET-OCT-IA and ET-Histo indicating that both methods can be utilized interchangeably. OCT using the line-traced image analysis of the B-scan appears to be a valid and relatively practicable method for the determination of ET in vivo. Furthermore, the comparisons with the in vivo OCT profiles demonstrate that cryostat sectioning provides a better preservation of relative and absolute dimensions of skin layers than paraffin embedding.

  7. Summary of Stress Analysis of CC Cryostat w/o Stiffening Rings

    SciTech Connect

    Wands, R.; /Fermilab

    1986-02-04

    A finite element model of the CC cryostat was used to investigate the stresses resulting in this structure under internal pressure (30 psi at the top of the vessel increasing linearly to 40 psi at the bottom) and weight loadings. Figures 1 and 2 show the model and relevant physical dimensions. The results are given in Table I. The stresses were extracted. from the nodal stress output for individual elements. The variation of stress over the element is some indication of mesh adequacy in the absence of additional results from a finer mesh. Based on this variation, the stresses output for the central cylinder and head appear to be quite good. The nodal stresses vary about 15% within the most highly stressed elements. The maximum stresses in the outer cylinder occur in the element defined by the four nodes used for support. Stresses within this element vary by a factor of {approx}2. It is fair to say that no detailed information on stresses in the shell at the support is available with this mesh. However, outer shell stresses away from the supports are well within the limits for SS 304 as given by Section VIII, Division 2, Appendix 4. A basic node map of the axisymmetric node pattern is shown in Fig. 3 as an aid in interpreting output. This pattern is repeated 25 times about the Y-axis, with an increment of 70 in node number, and an angular increment of 7.5{sup o}. It can be concluded from the stress results that stiffening rings are not necessary in the assembled central calorimeter cryostat due to the relatively short length of the vessel and the stiffening effects of the heads. Detailed stress results in the region of the supports will be investigated in the future with a refined local mesh.

  8. High-stability cryogenic scanning tunneling microscope based on a closed-cycle cryostat

    SciTech Connect

    Hackley, Jason D.; Kislitsyn, Dmitry A.; Beaman, Daniel K.; Nazin, George V.; Ulrich, Stefan

    2014-10-15

    We report on the design and operation of a cryogenic ultra-high vacuum (UHV) scanning tunneling microscope (STM) coupled to a closed-cycle cryostat (CCC). The STM is thermally linked to the CCC through helium exchange gas confined inside a volume enclosed by highly flexible rubber bellows. The STM is thus mechanically decoupled from the CCC, which results in a significant reduction of the mechanical noise transferred from the CCC to the STM. Noise analysis of the tunneling current shows current fluctuations up to 4% of the total current, which translates into tip-sample distance variations of up to 1.5 picometers. This noise level is sufficiently low for atomic-resolution imaging of a wide variety of surfaces. To demonstrate this, atomic-resolution images of Au(111) and NaCl(100)/Au(111) surfaces, as well as of carbon nanotubes deposited on Au(111), were obtained. Thermal drift analysis showed that under optimized conditions, the lateral stability of the STM scanner can be as low as 0.18 Å/h. Scanning Tunneling Spectroscopy measurements based on the lock-in technique were also carried out, and showed no detectable presence of noise from the closed-cycle cryostat. Using this cooling approach, temperatures as low as 16 K at the STM scanner have been achieved, with the complete cool-down of the system typically taking up to 12 h. These results demonstrate that the constructed CCC-coupled STM is a highly stable instrument capable of highly detailed spectroscopic investigations of materials and surfaces at the atomic scale.

  9. Gas tungsten arc welder

    DOEpatents

    Christiansen, D.W.; Brown, W.F.

    A welder for automated closure of fuel pins by a gas tungsten arc process in which a rotating length of cladding is positioned adjacent a welding electrode in a sealed enclosure. An independently movable axial grinder is provided in the enclosure for refurbishing the used electrode between welds.

  10. Arc Length Gone Global

    ERIC Educational Resources Information Center

    Boudreaux, Gregory M.; Wells, M. Scott

    2007-01-01

    Everyone with a thorough knowledge of single variable calculus knows that integration can be used to find the length of a curve on a given interval, called its arc length. Fortunately, if one endeavors to pose and solve more interesting problems than simply computing lengths of various curves, there are techniques available that do not require an…

  11. Thermal Arc Spray Overview

    NASA Astrophysics Data System (ADS)

    Hafiz Abd Malek, Muhamad; Hayati Saad, Nor; Kiyai Abas, Sunhaji; Mohd Shah, Noriyati

    2013-06-01

    Usage of protective coating for corrosion protection was on highly demand during the past decade; and thermal spray coating played a major part during that time. In recent years, the thermal arc spray coating becomes a popular coating. Many big players in oil and gas such as PETRONAS, EXXON MOBIL and SHELL in Malaysia tend to use the coating on steel structure as a corrosion protection. Further developments in coating processes, the devices, and raw materials have led to expansion of functional coatings and applications scope from conventional coating to specialized industries. It is widely used because of its ability to withstand high process temperature, offer advantages in efficiency, lower cost and acts as a corrosion protection. Previous research also indicated that the thermal arc spray offers better coating properties compared to other methods of spray. This paper reviews some critical area of thermal spray coating by discussing the process/parameter of thermal arc spray technology and quality control of coating. Coating performance against corrosion, wear and special characteristic of coating are also described. The field application of arc spray technology are demonstrated and reviewed.

  12. Variable polarity arc welding

    NASA Technical Reports Server (NTRS)

    Bayless, E. O., Jr.

    1991-01-01

    Technological advances generate within themselves dissatisfactions that lead to further advances in a process. A series of advances in welding technology which culminated in the Variable Polarity Plasma Arc (VPPA) Welding Process and an advance instituted to overcome the latest dissatisfactions with the process: automated VPPA welding are described briefly.

  13. Evolution of magnetically rotating arc into large area arc plasma

    NASA Astrophysics Data System (ADS)

    Wang, Cheng; Li, Wan-Wan; Zhang, Xiao-Ning; Zha, Jun; Xia, Wei-Dong

    2015-06-01

    An arc channel tends to shrink due to its conductivity increasing with the increase of temperature. In this study, to generate large area arc plasma, we construct a magnetically rotating arc plasma generator, which mainly consists of a lanthanide tungsten cathode (13 mm in diameter), a concentric cylindrical graphite anode chamber (60 mm in diameter) and a solenoid coil for producing an axial magnet field. By controlling the cold gas flow, the magnetically rotating arc evolves from constricted mode to diffuse mode, which almost fills the whole arc chamber cross section. Results show that the diffuse arc plasma has better uniformity and stability. The formation mechanism of large area arc plasma is discussed in this paper. Project supported by the National Natural Science Foundation of China (Grant Nos. 11035005, 11475174, and 50876101) and the Science Instrument Foundation of the Chinese Academy of Sciences (Grant No. Y201162).

  14. Hall-effect arc protector

    DOEpatents

    Rankin, R.A.; Kotter, D.K.

    1997-05-13

    The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored. 2 figs.

  15. Hall-effect arc protector

    DOEpatents

    Rankin, Richard A.; Kotter, Dale K.

    1997-01-01

    The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored.

  16. Differential preservation in the geologic record of intraoceanic arc sedimentary and tectonic processes

    NASA Astrophysics Data System (ADS)

    Draut, Amy E.; Clift, Peter D.

    2013-01-01

    Records of ancient intraoceanic arc activity, now preserved in continental suture zones, are commonly used to reconstruct paleogeography and plate motion, and to understand how continental crust is formed, recycled, and maintained through time. However, interpreting tectonic and sedimentary records from ancient terranes after arc-continent collision is complicated by preferential preservation of evidence for some arc processes and loss of evidence for others. In this synthesis we examine what is lost, and what is preserved, in the translation from modern processes to the ancient record of intraoceanic arcs. Composition of accreted arc terranes differs as a function of arc-continent collision geometry. 'Forward-facing' collision can accrete an oceanic arc on to either a passive or an active continental margin, with the arc facing the continent and colliding trench- and forearc-side first. In a 'backward-facing' collision, involving two subduction zones with similar polarity, the arc collides backarc-first with an active continental margin. The preservation of evidence for contemporary sedimentary and tectonic arc processes in the geologic record depends greatly on how well the various parts of the arc survive collision and orogeny in each case. Preservation of arc terranes likely is biased towards those that were in a state of tectonic accretion for tens of millions of years before collision, rather than tectonic erosion. The prevalence of tectonic erosion in modern intraoceanic arcs implies that valuable records of arc processes are commonly destroyed even before the arc collides with a continent. Arc systems are most likely to undergo tectonic accretion shortly before forward-facing collision with a continent, and thus most forearc and accretionary-prism material in ancient arc terranes likely is temporally biased toward the final stages of arc activity, when sediment flux to the trench was greatest and tectonic accretion prevailed. Collision geometry and tectonic

  17. HOLLOW CARBON ARC DISCHARGE

    DOEpatents

    Luce, J.S.

    1960-10-11

    A device is described for producing an energetic, direct current, hollow, carbon-arc discharge in an evacuated container and within a strong magnetic field. Such discharges are particularly useful not only in dissociation and ionization of high energy molecular ion beams, but also in acting as a shield or barrier against the instreaming of lowenergy neutral particles into a plasma formed within the hollow discharge when it is used as a dissociating mechanism for forming the plasma. There is maintained a predetermined ratio of gas particles to carbon particles released from the arc electrodes during operation of the discharge. The carbon particles absorb some of the gas particles and are pumped along and by the discharge out of the device, with the result that smaller diffusion pumps are required than would otherwise be necessary to dispose of the excess gas.

  18. ARC and Melting Efficiency of Plasma ARC Welds

    NASA Technical Reports Server (NTRS)

    McClure, J. C.; Nunes, A. C.; Evans, D. M.

    1999-01-01

    A series of partial penetration Variable Polarity Plasma Arc welds were made at equal power but various combinations of current and voltage on 2219 Aluminum. Arc efficiency was measured calorimetrically and ranged between 48% and 66% for the conditions of the welds. Arc efficiency depends in different ways on voltage and current. The voltage effect dominates. Raising voltage while reducing current increases arc efficiency. Longer, higher voltage arcs are thought to transfer a greater portion of arc power to the workpiece through shield gas convection. Melting efficiency depends upon weld pool shape as well as arc efficiency. Increased current increases the melting efficiency as it increases the depth to width ratio of the weld pool. Increased plasma gas flow does the same thing. Higher currents are thought to raise arc pressure and depress liquid at the bottom of the weld pool. More arc power then transfers to the workpiece through increasing plasma gas convection. If the power is held constant, the reduced voltage lowers the arc efficiency, while the pool shape change increases the melting efficiency,

  19. NASA GRC and MSFC Space-Plasma Arc Testing Procedures

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.; Vayner, Boris V.; Galofaro, Joel T.; Hillard, G. Barry; Vaughn, Jason; Schneider, Todd

    2007-01-01

    Tests of arcing and current collection in simulated space plasma conditions have been performed at the NASA Glenn Research Center (GRC) in Cleveland, Ohio, for over 30 years and at the Marshall Space Flight Center (MSFC) in Huntsville, Alabama, for almost as long. During this period, proper test conditions for accurate and meaningful space simulation have been worked out, comparisons with actual space performance in spaceflight tests and with real operational satellites have been made, and NASA has achieved our own internal standards for test protocols. It is the purpose of this paper to communicate the test conditions, test procedures, and types of analysis used at NASA GRC and MSFC to the space environmental testing community at large, to help with international space-plasma arcing-testing standardization. Discussed herein are neutral gas conditions, plasma densities and uniformity, vacuum chamber sizes, sample sizes and Debye lengths, biasing samples versus self-generated voltages, floating samples versus grounded samples, test electrical conditions, arc detection, preventing sustained discharges during testing, real samples versus idealized samples, validity of LEO tests for GEO samples, extracting arc threshold information from arc rate versus voltage tests, snapover, current collection, and glows at positive sample bias, Kapton pyrolysis, thresholds for trigger arcs, sustained arcs, dielectric breakdown and Paschen discharge, tether arcing and testing in very dense plasmas (i.e. thruster plumes), arc mitigation strategies, charging mitigation strategies, models, and analysis of test results. Finally, the necessity of testing will be emphasized, not to the exclusion of modeling, but as part of a complete strategy for determining when and if arcs will occur, and preventing them from occurring in space.

  20. The Role of Water Vapor and Dissociative Recombination Processes in Solar Array Arc Initiation

    NASA Technical Reports Server (NTRS)

    Galofar, J.; Vayner, B.; Degroot, W.; Ferguson, D.

    2002-01-01

    Experimental plasma arc investigations involving the onset of arc initiation for a negatively biased solar array immersed in low-density plasma have been performed. Previous studies into the arc initiation process have shown that the most probable arcing sites tend to occur at the triple junction involving the conductor, dielectric and plasma. More recently our own experiments have led us to believe that water vapor is the main causal factor behind the arc initiation process. Assuming the main component of the expelled plasma cloud by weight is water, the fastest process available is dissociative recombination (H2O(+) + e(-) (goes to) H* + OH*). A model that agrees with the observed dependency of arc current pulse width on the square root of capacitance is presented. A 400 MHz digital storage scope and current probe was used to detect arcs at the triple junction of a solar array. Simultaneous measurements of the arc trigger pulse, the gate pulse, the arc current and the arc voltage were then obtained. Finally, a large number of measurements of individual arc spectra were obtained in very short time intervals, ranging from 10 to 30 microseconds, using a 1/4 a spectrometer coupled with a gated intensified CCD. The spectrometer was systematically tuned to obtain optical arc spectra over the entire wavelength range of 260 to 680 nanometers. All relevant atomic lines and molecular bands were then identified.

  1. Arc jet diagnostics tests

    NASA Technical Reports Server (NTRS)

    Willey, Ronald J.

    1989-01-01

    Two objectives were addressed during a 10 week 1988 NASA/ASEE summer faculty fellowship at the Johnson Space Center Atmospheric Reentry Materials Structures Evaluation Facility (ARMSEF). These objectives were the evaluation of mass spectrometry for the measurement of atomic and molecular species in an arc jet environment, and the determination of atomic recombination coefficients for reaction cured glass (RCG) coated high temperature surface insulation (HRSI) materials subjected to simulated reentry conditions. Evaluation of mass spectrometry for the measurement of atomic and molecular species provided some of the first measurements of point compositions in arc jet tunnel environments. A major objective of this project centered around the sampling residence time. A three staged vacuum sampling system pulled the molecules and atoms from the arc jet to a quadrupole ionization mass spectrometer in 400 milliseconds. Conditions investigated included a composition survey across the nozzle exit at 3 cm z-distance from the nozzle exit for 3 different currents. Also, a point composition survey was taken around a shock created by the presence of a blunt body.

  2. Low Temperature Scanning Probe Microscope(LT-SPM) operating in a Cryogen-Free Cryostat, 1.5-300K

    NASA Astrophysics Data System (ADS)

    Karci, Ozgur; Dede, Munir; Bugoslavsky, Yury; Hall, Renny; Oral, Ahmet; Nanomagnetics Instruments Ltd. Team; Cryogenic Limited Team; Sabanci University Team

    2011-03-01

    We present the design of a Low Temperature Scanning Probe Microscope(LT-SFM) operating in a vibration-free cryogen-free cryostat. A 0.5W ultra now noise Pulse Tube cryocooler is integrated into the cryostat with a 9T magnet. Stick slip coarse approach mechanism is used to bring the sample in to close proximity of the sample. The sample can be moved in XY directions within 3 mm range, while the position is measured with capacitive encoder with 3 μ m accuracy. An improved fiber interferometer with ~ 12 fm/ √ Hz noise level is used to detect cantilever deflection. The resonance of the cantilever controlled by a digital Phase Locked Loop (PLL) integrated in our Control Electronics with 5mHz frequency resolution. We can achieve ~ 1 nm resolution in AFM mode & <10nm resolution in MFM mode. Results from different imaging modes; non-contact AFM, MFM, Piezoresponse, Conductive AFM etc. will be presented.

  3. Thermal Performance of Aged and Weathered Spray-On Foam Insulation (SOFI) Materials Under Cryogenic Vacuum Conditions (Cryostat-4)

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The NASA Cryogenics Test Laboratory at Kennedy Space Center conducted long-term testing of SOFI materials under actual-use cryogenic conditions with Cryostat-4. The materials included in the testing were NCFI 24-124 (acreage foam), BX-265 (close-out foam, including intertank flange and bipod areas), and a potential alternate material, NCFI 27-68, (acreage foam with the flame retardant removed). Specimens of these materials were placed at two locations: a site that simulated aging (the Vehicle Assembly Building [VAB]) and a site that simulated weathering (the Atmospheric Exposure Test Site [beach site]). After aging/weathering intervals of 3, 6, and 12 months, the samples were retrieved and tested for their thermal performance under cryogenic vacuum conditions with test apparatus Cryostat-4.

  4. Cryostat design and analysis of the superconducting magnets for Jefferson Lab's 11-GEV/C super high momentum spectrometer

    SciTech Connect

    P. Brindza, E. Sun, S. Lassiter, M. Fowler

    2010-04-01

    This paper describes the mechanical design and analysis of the cryostats for the two cos(2theta) quadrupoles and the cos(theta) dipole. All the magnets are currently being bid for commercial fabrication. The results of finite element analysis for the magnet cryostat helium vessels and outer vacuum chambers which investigate the mechanical integrity under maximum allowable internal working pressure, maximum allowable external working pressure, and cryogenic temperature are discussed. The allowable stress criterion is determined based on the allowable stress philosophy of the ASME codes. The computed cryogenic heat load of the magnets is compared with the allowable cryogenic consumption budget. The presented cool-down time of the magnets was studied under the conditions of a limited supply rate and a controlled temperature differential of 50 K in the magnets.

  5. Cryostat Design and Analysis of the Superconducting Magnets for Jefferson Lab's 11 Gev/c Super High Momentum Spectrometer

    NASA Astrophysics Data System (ADS)

    Brindza, P.; Sun, E.; Lassiter, S.; Fowler, M.

    2010-04-01

    This paper describes the mechanical design and analysis of the cryostats for the two cos(2θ) quadrupoles and the cos(θ) dipole. All the magnets are currently being bid for commercial fabrication. The results of finite element analysis for the magnet cryostat helium vessels and outer vacuum chambers which investigate the mechanical integrity under maximum allowable internal working pressure, maximum allowable external working pressure, and cryogenic temperature are discussed. The allowable stress criterion is determined based on the allowable stress philosophy of the ASME codes. The computed cryogenic heat load of the magnets is compared with the allowable cryogenic consumption budget. The presented cool-down time of the magnets was studied under the conditions of a limited supply rate and a controlled temperature differential of 50 K in the magnets.

  6. Handling and analysis of ices in cryostats and glove boxes in view of cometary samples

    NASA Technical Reports Server (NTRS)

    Roessler, K.; Eich, G.; Heyl, M.; Kochan, H.; Oehler, A.; Patnaik, A.; Schlosser, W.; Schulz, R.

    1989-01-01

    Comet nucleus sample return mission and other return missions from planets and satellites need equipment for handling and analysis of icy samples at low temperatures under vacuum or protective gas. Two methods are reported which were developed for analysis of small icy samples and which are modified for larger samples in cometary matter simulation experiments (KOSI). A conventional optical cryostat system was modified to allow for transport of samples at 5 K, ion beam irradiation, and measurement in an off-line optical spectrophotometer. The new system consists of a removable window plug containing nozzles for condensation of water and volatiles onto a cold finger. This plug can be removed in a vacuum system, changed against another plug (e.g., with other windows (IR, VIS, VUV) or other nozzles). While open, the samples can be treated under vacuum with cooling by manipulators (cut, removal, sample taking, irradiation with light, photons, or ions). After bringing the plug back, the samples can be moved to another site of analysis. For handling the 30 cm diameter mineral-ice samples from the KOSI experiments an 80x80x80 cm glove box made out of plexiglass was used. The samples were kept in a liquid nitrogen bath, which was filled from the outside. A stream a dry N2 and evaporating gas from the bath purified the glove box from impurity gases and, in particular, H2O, which otherwise would condense onto the samples.

  7. Cryostat section assay of oestrogen and progesterone receptors in meningiomas: a clinicopathological study.

    PubMed Central

    Ironside, J W; Battersby, R D; Dangerfield, V J; Parsons, M A; Timperley, W R; Underwood, J C

    1986-01-01

    Oestrogen receptors and progesterone receptors were measured in the cytosols from cryostat sections of 45 meningiomas from 40 patients (12 men, 28 women) using an isoelectric focusing technique. Near fascimile adjacent sections from the same tissue blocks were stained and examined to determine the histological subtype of the neoplasms. Appreciable levels of progesterone receptor (greater than 10 fmol/mg cytosol protein) were present in 24 (53.3%) of of the neoplasms, but no clinically important oestrogen receptor was detected in any of the tumours. Competitive binding studies on control tissue confirmed the specificity of the assay procedures. No correlation was found between progesterone receptor state and the age, sex, or menopausal state of the patients, or the histological subtype and site of the neoplasms. Four of the patients studied had multiple intracranial neoplasms, which in two were of differing progesterone receptor state. The presence of specific progesterone receptor in meningioma cytosols raises the possibility of hormonal manipulation in the treatment of this group of neoplasms. PMID:3950031

  8. Further tests of the Argonne 3. 3-MJ pulsed superconducting coil and its nonmetallic cryostat

    SciTech Connect

    Kim, S.; Krieger, C.; McGhee, D.

    1983-05-01

    A split-pair superconducting coil of the Pulsed Cable Test Facility (PCTF) at Argonne National Laboratory (ANL) has been successfully tested both in DC and pulsing modes. At a peak operating current of 11 kA, the peak magnetic field and stored energy of the coil are 6.5 T and 3.3 MJ, respectively. In the pulsing test, the coil was charged to 10.55 kA in 1.0 s and discharged to zero in 1.6 s. The ac losses of the coil in this mode were 7.5 kJ/pulse. The coil is composed of two solenoids each with 22 layers and 9.14 turns per layer. The cable for the coil consists of 24, 19-strand NbTi subcables. The nonmetallic cryostat of the PCTF consists of two fiberglass reinforced polyester resin vessels. Developmental high current conductors can be tested under the PCTF pulsing magnetic fields in a form of pancake coils or as a short sample for the studies of pulsing effects.

  9. Closing a quantum feedback loop for a superconducting qubit inside a cryostat

    NASA Astrophysics Data System (ADS)

    Andersen, Christian Kraglund; Kerckhoff, Joseph; Lehnert, Konrad W.; Chapman, Benjamin J.; Mølmer, Klaus

    Several quantum information protocols relies upon efficient feedback (or feed-forward) schemes. Recently, within the field of superconducting qubits, many experiments have shown tremendous progress towards high fidelity quantum feedback scheme. Some experiments work by traditional measurement based schemes where the classical output is processed on a classical ''computer'' before a signal is fed back to the qubits. Other approaches are working in a continuous coherent manner, where the full quantum description of the system creates an effective bath that relaxes the system into the desired state. This talk will present a different approach that aims to close a measurement based feedback loop inside a cryostat and, thus, the scheme works completely autonomous. This approach sidesteps many of the inefficiencies inherent in two-way communication between temperature stages in typical systems with room temperature controllers, and avoids increasing the cryogenic heat load. This controller may find a broad range of uses in multi-qubit systems, but here I analyze two specific demonstrative cases in single qubit-control and show simulations of the time evolution for the full system dynamics.

  10. Modeling the pressure increase in liquid helium cryostats after failure of the insulating vacuum

    NASA Astrophysics Data System (ADS)

    Heidt, C.; Grohmann, S.; Süßer, M.

    2014-01-01

    The pressure relief system of liquid helium cryostats requires a careful design, due to helium's low enthalpy of vaporization and due to the low operating temperature. Hazard analyses often involve the failure of the insulating vacuum in the worst-case scenario. The venting of the insulating vacuum and the implications for the pressure increase in the helium vessel, however, have not yet been fully analyzed. Therefore, the dimensioning of safety devices often requires experience and reference to very few experimental data. In order to provide a better foundation for the design of cryogenic pressure relief systems, this paper presents an analytic approach for the strongly dynamic process induced by the loss of insulating vacuum. The model is based on theoretical considerations and on differential equation modeling. It contains only few simplifying assumptions, which will be further investigated in future experiments. The numerical solutions of example calculations are presented with regard to the heat flux into the helium vessel, the helium pressure increase and the helium flow rate through the pressure relief device. Implications concerning two-phase flow and the influence of kinetic energy are discussed.

  11. Modeling the pressure increase in liquid helium cryostats after failure of the insulating vacuum

    SciTech Connect

    Heidt, C.; Grohmann, S.; Süßer, M.

    2014-01-29

    The pressure relief system of liquid helium cryostats requires a careful design, due to helium's low enthalpy of vaporization and due to the low operating temperature. Hazard analyses often involve the failure of the insulating vacuum in the worst-case scenario. The venting of the insulating vacuum and the implications for the pressure increase in the helium vessel, however, have not yet been fully analyzed. Therefore, the dimensioning of safety devices often requires experience and reference to very few experimental data. In order to provide a better foundation for the design of cryogenic pressure relief systems, this paper presents an analytic approach for the strongly dynamic process induced by the loss of insulating vacuum. The model is based on theoretical considerations and on differential equation modeling. It contains only few simplifying assumptions, which will be further investigated in future experiments. The numerical solutions of example calculations are presented with regard to the heat flux into the helium vessel, the helium pressure increase and the helium flow rate through the pressure relief device. Implications concerning two-phase flow and the influence of kinetic energy are discussed.

  12. Mesh sensitivity study and optimization of fixed support for ITER torus and cryostat cryoline

    NASA Astrophysics Data System (ADS)

    Badgujar, S.; Vaghela, H.; Shah, N.; Bhattacharya, R.; Sarkar, B.

    2010-02-01

    The torus & cryostat cryoline of ITER cryodistribution system has been designed as per the process specifications. The cryoline is an ensemble of six process pipes, thermal shield, fixed, sliding support and outer jacket. The fixed support (FS), which also acts as the anchor for the bellows, is one of the most important part of the cryoline. The FS has to withstand the static weight of pipes as well as the spring and thrust forces arising from the bellows. The FS design has been optimized for the thermal, structural and for combined loads with thermal optimization criteria; less than 8 Watt at 100 K and less than 1.5 Watt at 4.5 K. ANSYS 10.0 has been used for the analysis and CATIA V5 R16 has been used for the modelling as well as geometry optimization. In order to bring the Von-Mises stress within the acceptable limit of 115 MPa, a detailed mesh sensitivity study has been carried out along with design optimization. The iterative process of mesh refinement continued till stress convergence is achieved. The stress analysis has been carried out for optimized mesh size. The paper will present the design methodology, construction details and the results of the analysis.

  13. A flying superconducting magnet and cryostat for magnetic suspension of wind-tunnel models

    NASA Technical Reports Server (NTRS)

    Britcher, C.; Goodyer, M. J.; Scurlock, R. G.; Wu, Y. Y.

    1984-01-01

    The engineering practicality of a persistent high-field superconducting solenoid cryostat as a magnetic suspension and balance system (MSBS) for wind-tunnel testing of aircraft and missile models is examined. The test apparatus is a simple solenoid of filamentary NbTi superconductor with a cupronickel matrix. The apparatus, with a length-to-diameter ratio of 6 to 1 and a radius of 32 mm, used a 0.25 mm wire with a critical current of 27 A in an external field of 6 T. The total heat inleak of 150 mW was achieved. Helium boiloff rates were tested over a range of operating conditions, including pitch attitudes from 10 deg nose down to 90 deg nose up; the rate was estimated as low, but the aerodynamic acceptability of venting gaseous helium has not been determined. It is shown that the effectiveness of the concept increases with increasing scale, and performance in excess of that of conventional ferromagnets is achievable with reduction in size and costs, and with aptness to transonic wind-tunnel testing. Detailed specifications and schematics are included.

  14. Spectroscopic study of the reaction of silver atoms with CO in a rotating cryostat

    SciTech Connect

    Chenier, J.H.B.; Hampson, C.A.; Howard, J.A.; Mile, B.

    1988-05-19

    Reactions of /sup 107/Ag atoms with CO have been studied in inert hydrocarbon matrices in a rotating cryostat at cryogenic temperatures by EPR and FTIR spectroscopies. AgCO, bent Ag(CO)/sub 2/ two conformers of Ag(CO)/sub 3/, and cluster carbonyls Ag/sub n/(CO)/sub x/, where n greater than or equal to 5, are formed in adamantane. Magnetic parameters are reported for these silver carbonyls. IR spectra show the presence of a range of carbon monoxide complexes with single Ag atoms and Ag clusters, but the considerable overlapping of the bands from all these species precludes assignment other than that at 1952 cm/sup -1/ to planar Ag(CO)/sub 3/. In cyclohexane unambiguous EPR or FTIR evidence for mononuclear AG carbonyls is not obtained, but there are strong complex features in both spectra from a range of Ag cluster carbonyls AG/sub n/(CO)/sub x/ with n = 2-7.

  15. Radiation of long and high power arcs

    NASA Astrophysics Data System (ADS)

    Cressault, Y.; Bauchire, J. M.; Hong, D.; Rabat, H.; Riquel, G.; Sanchez, F.; Gleizes, A.

    2015-10-01

    The operators working on electrical installations of low, medium and high voltages can be accidentally exposed to short-circuit arcs ranging from a few kA to several tens of kA. To protect them from radiation, according to the exposure limits, we need to characterize the radiation emitted by the powerful arc. Therefore, we have developed a general experimental and numerical study in order to estimate the spectral irradiance received at a given distance from the arc. The experimental part was based on a very long arc (up to 2 m) with high ac current (between 4 and 40 kA rms, duration 100 ms) using 3 kinds of metallic contacts (copper, steel and aluminium). We measured the irradiance received 10m from the axis of the arc, and integrated on 4 spectral intervals corresponding to the UV, visible, IRA  +  B and IRC. The theoretical part consisted of calculating the radiance of isothermal plasmas in mixtures of air and metal vapour, integrated over the same spectral intervals as defined in the experiments. The comparison between the theoretical and experimental results has allowed the defining of three isothermal radiation sources whose combination leads to a spectral irradiation equivalent to the experimental one. Then the calculation allowed the deduction of the spectral description of the irradiance over all the wavelength range, between 200 nm and 20 μm. The final results indicate that the influence of metal is important in the visible and UVA ranges whereas the IR radiation is due to the air plasma and surrounding hot gas and fumes.

  16. Arc melter demonstration baseline test results

    SciTech Connect

    Soelberg, N.R.; Chambers, A.G.; Anderson, G.L.; Oden, L.L.; O`Connor, W.K.; Turner, P.C.

    1994-07-01

    This report describes the test results and evaluation for the Phase 1 (baseline) arc melter vitrification test series conducted for the Buried Waste Integrated Demonstration program (BWID). Phase 1 tests were conducted on surrogate mixtures of as-incinerated wastes and soil. Some buried wastes, soils, and stored wastes at the INEL and other DOE sites, are contaminated with transuranic (TRU) radionuclides and hazardous organics and metals. The high temperature environment in an electric arc furnace may be used to process these wastes to produce materials suitable for final disposal. An electric arc furnace system can treat heterogeneous wastes and contaminated soils by (a) dissolving and retaining TRU elements and selected toxic metals as oxides in the slag phase, (b) destroying organic materials by dissociation, pyrolyzation, and combustion, and (c) capturing separated volatilized metals in the offgas system for further treatment. Structural metals in the waste may be melted and tapped separately for recycle or disposal, or these metals may be oxidized and dissolved into the slag. The molten slag, after cooling, will provide a glass/ceramic final waste form that is homogeneous, highly nonleachable, and extremely durable. These features make this waste form suitable for immobilization of TRU radionuclides and toxic metals for geologic timeframes. Further, the volume of contaminated wastes and soils will be substantially reduced in the process.

  17. Design and Operation of A Setup with A Camera and Adjustable Mirror to Inspect the Sense-Wire Planes of the Time Projection Chamber Inside the MicroBooNE Cryostat

    DOE PAGESBeta

    Carls, Benjamin; Horton-Smith, Glenn; James, Catherine C.; Kubinski, Robert M.; Pordes, Stephen; Schukraft, Anne; Strauss, Thomas

    2015-08-26

    Detectors in particle physics, particularly when including cryogenic components, are often enclosed in vessels that do not provide any physical or visual access to the detectors themselves after installation. However, it can be desirable for experiments to visually investigate the inside of the vessel. The MicroBooNE cryostat hosts a TPC with sense-wire planes, which had to be inspected for damage such as breakage or sagging. This inspection was performed after the transportation of the vessel with the enclosed detector to its final location, but before filling with liquid argon. Our paper describes an approach to view the inside of themore » MicroBooNE cryostat with a setup of a camera and a mirror through one of its cryogenic service nozzles. The paper also describes the camera and mirror chosen for the operation, the illumination, and the mechanical structure of the setup. It explains how the system was operated and demonstrates its performance.« less

  18. Controlling Arc Length in Plasma Welding

    NASA Technical Reports Server (NTRS)

    Iceland, W. F.

    1986-01-01

    Circuit maintains arc length on irregularly shaped workpieces. Length of plasma arc continuously adjusted by control circuit to maintain commanded value. After pilot arc is established, contactor closed and transfers arc to workpiece. Control circuit then half-wave rectifies ac arc voltage to produce dc control signal proportional to arc length. Circuit added to plasma arc welding machines with few wiring changes. Welds made with circuit cleaner and require less rework than welds made without it. Beads smooth and free of inclusions.

  19. A method for eliminating Faraday rotation in cryostat windows in longitudinal magneto-optical Kerr effect measurements

    SciTech Connect

    Polewko-Klim, A. Uba, S.; Uba, L.

    2014-07-15

    A solution to the problem of disturbing effect of the background Faraday rotation in the cryostat windows on longitudinal magneto-optical Kerr effect (LMOKE) measured under vacuum conditions and/or at low temperatures is proposed. The method for eliminating the influence of Faraday rotation in cryostat windows is based on special arrangement of additional mirrors placed on sample holder. In this arrangement, the orientation of the cryostat window is perpendicular to the light beam direction and parallel to an external magnetic field generated by the H-frame electromagnet. The operation of the LMOKE magnetometer with the special sample holder based on polarization modulation technique with a photo-elastic modulator is theoretically analyzed with the use of Jones matrices, and formulas for evaluating of the actual Kerr rotation and ellipticity of the sample are derived. The feasibility of the method and good performance of the magnetometer is experimentally demonstrated for the LMOKE effect measured in Fe/Au multilayer structures. The influence of imperfect alignment of the magnetometer setup on the Kerr angles, as derived theoretically through the analytic model and verified experimentally, is examined and discussed.

  20. Low vibration cooling using a pulse tube cooler and cryostat for the GRAVITY beam combiner instrument at the VLTI

    NASA Astrophysics Data System (ADS)

    Haug, M.; Haussmann, F.; Kellner, S.; Kern, L.; Eisenhauer, F.; Lizon, J.-L.; Dietrich, M.; Thummes, G.

    2014-07-01

    GRAVITY is a second generation VLTI instrument for high-precision narrow-angle astrometry and phase-referenced interferometric imaging in the astronomical K-band. The cryostat of the beam combiner instrument provides the required temperatures for the various subunits ranging from 40K to 290K with a milli-Kelvin temperature stability for some selected units. The bath cryostat is cooled with liquid nitrogen and makes use of the exhaust gas to cool the main optical bench to an intermediate temperature of 240K. The fringe tracking detector will be cooled separately by a single-stage pulse tube cooler to a temperature of 40K. The pulse tube cooler is optimized for minimum vibrations. In particular its warm side is connected to the 80K reservoir of the LN2 cryostat to minimize the required input power. All temperature levels are actively stabilized by electric heaters. The cold bench is supported separately from the vacuum vessel and the liquid nitrogen reservoir to minimize the transfer of acoustic noise onto the instrument.

  1. A method for eliminating Faraday rotation in cryostat windows in longitudinal magneto-optical Kerr effect measurements.

    PubMed

    Polewko-Klim, A; Uba, S; Uba, L

    2014-07-01

    A solution to the problem of disturbing effect of the background Faraday rotation in the cryostat windows on longitudinal magneto-optical Kerr effect (LMOKE) measured under vacuum conditions and/or at low temperatures is proposed. The method for eliminating the influence of Faraday rotation in cryostat windows is based on special arrangement of additional mirrors placed on sample holder. In this arrangement, the orientation of the cryostat window is perpendicular to the light beam direction and parallel to an external magnetic field generated by the H-frame electromagnet. The operation of the LMOKE magnetometer with the special sample holder based on polarization modulation technique with a photo-elastic modulator is theoretically analyzed with the use of Jones matrices, and formulas for evaluating of the actual Kerr rotation and ellipticity of the sample are derived. The feasibility of the method and good performance of the magnetometer is experimentally demonstrated for the LMOKE effect measured in Fe/Au multilayer structures. The influence of imperfect alignment of the magnetometer setup on the Kerr angles, as derived theoretically through the analytic model and verified experimentally, is examined and discussed. PMID:25085126

  2. Thermal and structural performance of a single tube support post for the Superconducting Super Collider dipole magnet cryostat

    SciTech Connect

    Boroski, W.N.; Nicol, T.H.; Ruschman, M.K.; Schoo, C.J.

    1993-07-01

    The reentrant support post currently incorporated in the Superconducting Super Collider (SSC) dipole cryostat has been shown to meet the structural and thermal requirements of the cryostat, both in prototype magnet assemblies and through component testing. However, the reentrant post design has two major drawbacks: tight dimensional control on all components, and cost driven by these tolerance constraints and a complex assembly procedure. A single tube support post has been developed as an alternative to the reentrant post design. Several prototype assemblies have been fabricated and subjected to structural testing. Compressive, tensile, and bending forces were applied to each assembly with deflection measured at several locations. A prototype support post has also been thermally evaluated in a heat leak measurement facility. Heat load to 4.2 K was measured with the intermediate post intercept operating at various temperatures while thermometers positioned along the conductive path of the post mapped thermal gradients. Results from these measurements indicate the single tube support post meets the design criteria for the SSC dipole magnet cryostat support system.

  3. Electrical Safety and Arc Flash Protections

    SciTech Connect

    R. Camp

    2008-03-04

    Over the past four years, the Electrical Safety Program at PPPL has evolved in addressing changing regulatory requirements and lessons learned from accident events, particularly in regards to arc flash hazards and implementing NFPA 70E requirements. This presentation will discuss PPPL's approaches to the areas of electrical hazards evaluation, both shock and arc flash; engineered solutions for hazards mitigation such as remote racking of medium voltage breakers, operational changes for hazards avoidance, targeted personnel training and hazard appropriate personal protective equipment. Practical solutions for nominal voltage identification and zero voltage checks for lockout/tagout will also be covered. Finally, we will review the value of a comprehensive electrical drawing program, employee attitudes expressed as a personal safety work ethic, integrated safety management, and sustained management support for continuous safety improvement.

  4. The volcanoes of an oceanic arc from origin to destruction: A case from the northern Luzon Arc

    NASA Astrophysics Data System (ADS)

    Lai, Yu-Ming; Song, Sheng-Rong

    2013-09-01

    Volcanoes were created, grew, uplifted, became dormant or extinct, and were accreted as part of continents during continuous arc-continent collision. Volcanic rocks in Eastern Taiwan's Coastal Range (CR) are part of the northern Luzon Arc, an oceanic island arc produced by the subduction of the South China Sea Plate beneath the Philippine Sea Plate. Igneous rocks are characterized by intrusive bodies, lava and pyroclastic flows, and volcaniclastic rocks with minor tephra deposits. Based on volcanic facies associations, Sr-Nd isotopic geochemistry, and the geography of the region, four volcanoes were identified in the CR: Yuemei, Chimei, Chengkuangao, and Tuluanshan. Near-vent facies associations show different degrees of erosion in the volcanic edifices for Chimei, Chengkuangao, and Tuluanshan. Yuemei lacks near-vent rocks, implying that Yuemei's main volcanic body may have been subducted at the Ryukyu Trench with the northward motion of the Philippine Sea Plate. These data suggest a hypothesis for the evolution of volcanism and geomorphology during arc growth and ensuing arc-continent collision in the northern Luzon Arc, which suggests that these volcanoes were formed from the seafloor, emerging as islands during arc volcanism. They then became dormant or extinct during collision, and finally, were uplifted and accreted by additional collision. The oldest volcano, Yuemei, may have already been subducted into the Ryukyu Trench.

  5. APPARATUS FOR ARC WELDING

    DOEpatents

    Lingafelter, J.W.

    1960-04-01

    An apparatus is described in which a welding arc created between an annular electrode and a workpiece moves under the influence of an electromagnetic field about the electrode in a closed or annular path. This mode of welding is specially suited to the enclosing of nuclear-fuel slugs in a protective casing. For example, a uranium slug is placed in an aluminum can, and an aluminum closure is welded to the open end of the can along a closed or annular path conforming to the periphery of the end closure.

  6. FusionArc optimization: A hybrid volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) planning strategy

    SciTech Connect

    Matuszak, Martha M.; McShan, Daniel L.; Ten Haken, Randall K.; Steers, Jennifer M.; Long, Troy; Edwin Romeijn, H.; Fraass, Benedick A.

    2013-07-15

    Purpose: To introduce a hybrid volumetric modulated arc therapy/intensity modulated radiation therapy (VMAT/IMRT) optimization strategy called FusionArc that combines the delivery efficiency of single-arc VMAT with the potentially desirable intensity modulation possible with IMRT.Methods: A beamlet-based inverse planning system was enhanced to combine the advantages of VMAT and IMRT into one comprehensive technique. In the hybrid strategy, baseline single-arc VMAT plans are optimized and then the current cost function gradients with respect to the beamlets are used to define a metric for predicting which beam angles would benefit from further intensity modulation. Beams with the highest metric values (called the gradient factor) are converted from VMAT apertures to IMRT fluence, and the optimization proceeds with the mixed variable set until convergence or until additional beams are selected for conversion. One phantom and two clinical cases were used to validate the gradient factor and characterize the FusionArc strategy. Comparisons were made between standard IMRT, single-arc VMAT, and FusionArc plans with one to five IMRT/hybrid beams.Results: The gradient factor was found to be highly predictive of the VMAT angles that would benefit plan quality the most from beam modulation. Over the three cases studied, a FusionArc plan with three converted beams achieved superior dosimetric quality with reductions in final cost ranging from 26.4% to 48.1% compared to single-arc VMAT. Additionally, the three beam FusionArc plans required 22.4%-43.7% fewer MU/Gy than a seven beam IMRT plan. While the FusionArc plans with five converted beams offer larger reductions in final cost-32.9%-55.2% compared to single-arc VMAT-the decrease in MU/Gy compared to IMRT was noticeably smaller at 12.2%-18.5%, when compared to IMRT.Conclusions: A hybrid VMAT/IMRT strategy was implemented to find a high quality compromise between gantry-angle and intensity-based degrees of freedom. This

  7. FusionArc optimization: A hybrid volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) planning strategy

    PubMed Central

    Matuszak, Martha M.; Steers, Jennifer M.; Long, Troy; McShan, Daniel L.; Fraass, Benedick A.; Edwin Romeijn, H.; Ten Haken, Randall K.

    2013-01-01

    Purpose: To introduce a hybrid volumetric modulated arc therapy/intensity modulated radiation therapy (VMAT/IMRT) optimization strategy called FusionArc that combines the delivery efficiency of single-arc VMAT with the potentially desirable intensity modulation possible with IMRT. Methods: A beamlet-based inverse planning system was enhanced to combine the advantages of VMAT and IMRT into one comprehensive technique. In the hybrid strategy, baseline single-arc VMAT plans are optimized and then the current cost function gradients with respect to the beamlets are used to define a metric for predicting which beam angles would benefit from further intensity modulation. Beams with the highest metric values (called the gradient factor) are converted from VMAT apertures to IMRT fluence, and the optimization proceeds with the mixed variable set until convergence or until additional beams are selected for conversion. One phantom and two clinical cases were used to validate the gradient factor and characterize the FusionArc strategy. Comparisons were made between standard IMRT, single-arc VMAT, and FusionArc plans with one to five IMRT/hybrid beams. Results: The gradient factor was found to be highly predictive of the VMAT angles that would benefit plan quality the most from beam modulation. Over the three cases studied, a FusionArc plan with three converted beams achieved superior dosimetric quality with reductions in final cost ranging from 26.4% to 48.1% compared to single-arc VMAT. Additionally, the three beam FusionArc plans required 22.4%–43.7% fewer MU/Gy than a seven beam IMRT plan. While the FusionArc plans with five converted beams offer larger reductions in final cost—32.9%–55.2% compared to single-arc VMAT—the decrease in MU/Gy compared to IMRT was noticeably smaller at 12.2%–18.5%, when compared to IMRT. Conclusions: A hybrid VMAT/IMRT strategy was implemented to find a high quality compromise between gantry-angle and intensity-based degrees of freedom

  8. Electric arc heater is self starting

    NASA Technical Reports Server (NTRS)

    Brown, R. D.

    1966-01-01

    Remote method initiates an electric arc over a large range of gaps between two water-cooled electrodes of an arc-heated wind tunnel without disassembling the arc unit. This type of starting system can be used on both three-phase ac arc heaters and dc arc heaters.

  9. Electric arc welding gun

    DOEpatents

    Luttrell, Edward; Turner, Paul W.

    1978-01-01

    This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

  10. Critical current measurements of high Tc superconductors in a scanning low temperature cryostat

    SciTech Connect

    Telschow, K.L.; O'Brien, T.K.

    1991-01-01

    Maintaining uniformity of properties over long distances is one of the fabrication problems encountered with the new high {Tc} superconductors. Uniform properties are crucial in long tapes or wires with high critical current since local nonuniformities can limit the current carrying capacity of the whole piece. Transport critical currents in high {Tc} superconductors are conventionally measured with the contact 4-point probe DC current-voltage technique. This technique requires contact with the sample and and spatially averages over the region between the two voltage contacts. Two techniques have been used to infer the critical state model. The first uses the net magnetization of a suitably shaped sample in an external magnetic field. The second combines a DC magnetic field with AC induced currents to infer spatial flux profiles. The AC magnetization technique offers an advantage in that it is noncontacting; however, it also averages the measurement over a large area and requires that the sample be shaped and positioned such that it exhibits zero demagnetizing factor. This paper describes a measurement technique and a scanning cryostat assembly that are capable of determining local critical current in a tape or wire with high resolution and without any direct sample electrical contact. A small compensated coil was used to induce AC currents in slab-shaped samples. The coil was situated near the surface on one side of the slab. With this method, the AC probe can be used as a noncontacting dissipation probe, replacing the voltage probe in the 4-point contact method, when an externally driven transport current is used, or by itself as a local critical state generator and dissipation detector. The results are shown to be meaningful even when the internal magnetic field is not uniform due to shape demagnetizing effects. 10 refs., 5 figs.

  11. Nitrite Reductase and Nitric-oxide Synthase Activity of the Mitochondrial Molybdopterin Enzymes mARC1 and mARC2*

    PubMed Central

    Sparacino-Watkins, Courtney E.; Tejero, Jesús; Sun, Bin; Gauthier, Marc C.; Thomas, John; Ragireddy, Venkata; Merchant, Bonnie A.; Wang, Jun; Azarov, Ivan; Basu, Partha; Gladwin, Mark T.

    2014-01-01

    Mitochondrial amidoxime reducing component (mARC) proteins are molybdopterin-containing enzymes of unclear physiological function. Both human isoforms mARC-1 and mARC-2 are able to catalyze the reduction of nitrite when they are in the reduced form. Moreover, our results indicate that mARC can generate nitric oxide (NO) from nitrite when forming an electron transfer chain with NADH, cytochrome b5, and NADH-dependent cytochrome b5 reductase. The rate of NO formation increases almost 3-fold when pH was lowered from 7.5 to 6.5. To determine if nitrite reduction is catalyzed by molybdenum in the active site of mARC-1, we mutated the putative active site cysteine residue (Cys-273), known to coordinate molybdenum binding. NO formation was abolished by the C273A mutation in mARC-1. Supplementation of transformed Escherichia coli with tungsten facilitated the replacement of molybdenum in recombinant mARC-1 and abolished NO formation. Therefore, we conclude that human mARC-1 and mARC-2 are capable of catalyzing reduction of nitrite to NO through reaction with its molybdenum cofactor. Finally, expression of mARC-1 in HEK cells using a lentivirus vector was used to confirm cellular nitrite reduction to NO. A comparison of NO formation profiles between mARC and xanthine oxidase reveals similar Kcat and Vmax values but more sustained NO formation from mARC, possibly because it is not vulnerable to autoinhibition via molybdenum desulfuration. The reduction of nitrite by mARC in the mitochondria may represent a new signaling pathway for NADH-dependent hypoxic NO production. PMID:24500710

  12. Alternating-Polarity Arc Welding

    NASA Technical Reports Server (NTRS)

    Schwinghamer, R. J.

    1987-01-01

    Brief reversing polarity of welding current greatly improves quality of welds. NASA technical memorandum recounts progress in art of variable-polarity plasma-arc (VPPA) welding, with emphasis on welding of aluminum-alloy tanks. VPPA welders offer important advantages over conventional single-polarity gas/tungsten arc welders.

  13. TAMA. TIGER Arc Modification Application

    SciTech Connect

    Armstrong, H.

    1994-06-03

    The application enables the geometric correction of TIGER arcs to a more accurate spatial data set. This is done in a structured automated environment according to Census Bureau guidelines and New Mexico state GIS standards. Arcs may be deleted, added, combined, split, and moved relative to a coverage or image displayed in the background.

  14. Of Eggs and Arcs

    NASA Astrophysics Data System (ADS)

    Burns, Joseph A.; Thomas, P. C.; Helfenstein, P.; Tiscareno, M. S.; Hedman, M. M.; Agarwal, M.

    2012-10-01

    New scenarios for the origins of Saturn’s rings/interior moons have directed scientific attention to the region just exterior to Saturn’s main rings. Four satellites (Aegaeon = Ae; Anthe = An; Methone = Me; Pallene = Pa) discovered by the Cassini mission on either side of Mimas’s orbit perhaps comprise a distinct class of ring-moon. They are tiny (R = 0.3-2.5 km); three (AeAnMe) are trapped in co-rotation resonances with Mimas and reside within ring-arcs; and at least two (MePa) have remarkably regular shapes. Images with pixel scales as fine as 27 m taken in May 2012 reveal Methone to be ovoid within 10 m (from sub-pixel limb detection) and devoid of any craters (>130 m) across its 9 km2 of surface; Pallene and even tiny Aegaeon have similar appearances in lesser-quality images. Numerical simulations demonstrate that particles comprising the surrounding ring-arcs populate the same resonances as their embedded moons; escape speeds from the moons are < 0.5 m/s, smaller than the 2 m/s that dynamically characterize the resonant well. We investigate the gentle transfer of particles back and forth between the ring-arcs and any embedded bodies. In this environment, the moons’ shapes are smooth equipotentials; electrostatic effects may also determine how grains settle to surfaces. Considering these shapes to represent equipotential surfaces for rotating, tidally distorted, homogeneous bodies, we infer mean satellite densities of 250+/-60 (Pa), 310+/-30 (Me), and 540+/-120 (Ae) kg m-3. About half of Methone’s leading hemisphere is covered by a sharply bounded, lemon-shaped, relatively dark region, having a form reminiscent of Mimas’s thermal anomaly (Howett et al. 2011). Its (601 nm) albedo is 13% lower than the bounding brighter material. An irregularly shaped, even-darker (by 4%) blotch straddles the apex of the moon’s motion. Impacts with circum-planetary meteoroids and plasma are likely responsible for these features.

  15. Laser Assisted Plasma Arc Welding

    SciTech Connect

    FUERSCHBACH,PHILLIP W.

    1999-10-05

    Experiments have been performed using a coaxial end-effecter to combine a focused laser beam and a plasma arc. The device employs a hollow tungsten electrode, a focusing lens, and conventional plasma arc torch nozzles to co-locate the focused beam and arc on the workpiece. Plasma arc nozzles were selected to protect the electrode from laser generated metal vapor. The project goal is to develop an improved fusion welding process that exhibits both absorption robustness and deep penetration for small scale (< 1.5 mm thickness) applications. On aluminum alloys 6061 and 6111, the hybrid process has been shown to eliminate hot cracking in the fusion zone. Fusion zone dimensions for both stainless steel and aluminum were found to be wider than characteristic laser welds, and deeper than characteristic plasma arc welds.

  16. Arc fault detection system

    DOEpatents

    Jha, K.N.

    1999-05-18

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.

  17. Arc fault detection system

    DOEpatents

    Jha, Kamal N.

    1999-01-01

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard.

  18. An arc-sequencing algorithm for intensity modulated arc therapy

    SciTech Connect

    Shepard, D. M.; Cao, D.; Afghan, M. K. N.; Earl, M. A.

    2007-02-15

    Intensity modulated arc therapy (IMAT) is an intensity modulated radiation therapy delivery technique originally proposed as an alternative to tomotherapy. IMAT uses a series of overlapping arcs to deliver optimized intensity patterns from each beam direction. The full potential of IMAT has gone largely unrealized due in part to a lack of robust and commercially available inverse planning tools. To address this, we have implemented an IMAT arc-sequencing algorithm that translates optimized intensity maps into deliverable IMAT plans. The sequencing algorithm uses simulated annealing to simultaneously optimize the aperture shapes and weights throughout each arc. The sequencer enforces the delivery constraints while minimizing the discrepancies between the optimized and sequenced intensity maps. The performance of the algorithm has been tested for ten patient cases (3 prostate, 3 brain, 2 head-and-neck, 1 lung, and 1 pancreas). Seven coplanar IMAT plans were created using an average of 4.6 arcs and 685 monitor units. Additionally, three noncoplanar plans were created using an average of 16 arcs and 498 monitor units. The results demonstrate that the arc sequencer can provide efficient and highly conformal IMAT plans. An average sequencing time of approximately 20 min was observed.

  19. Recent advances in vacuum arc ion sources

    SciTech Connect

    Brown, I.G.; Anders, A.; Anders, S.; Dickinson, M.R.; MacGill, R.A.; Oks, E.M.

    1995-07-01

    Intense beams of metal ions can be formed from a vacuum arc ion source. Broadbeam extraction is convenient, and the time-averaged ion beam current delivered downstream can readily be in the tens of milliamperes range. The vacuum arc ion source has for these reasons found good application for metallurgical surface modification--it provides relatively simple and inexpensive access to high dose metal ion implantation. Several important source developments have been demonstrated recently, including very broad beam operation, macroparticle removal, charge state enhancement, and formation of gaseous beams. The authors have made a very broad beam source embodiment with beam formation electrodes 50 cm in diameter, producing a beam of width {approximately}35 cm for a nominal beam area of {approximately}1,000 cm{sup 2}, and a pulsed Ti beam current of about 7 A was formed at a mean ion energy of {approximately}100 keV. Separately, they`ve developed high efficiency macroparticle-removing magnetic filters and incorporated such a filter into a vacuum arc ion source so as to form macroparticle-free ion beams. Jointly with researchers at the High Current Electronics Institute at Tomsk, Russia, and the Gesellschaft fuer Schwerionenforschung at Darmstadt, Germany, they`ve developed a compact technique for increasing the charge states of ions produced in the vacuum arc plasma and thus providing a simple means of increasing the ion energy at fixed extractor voltage. Finally, operation with mixed metal and gaseous ion species has been demonstrated. Here, they briefly review the operation of vacuum marc ion sources and the typical beam and implantation parameters that can be obtained, and describe these source advances and their bearing on metal ion implantation applications.

  20. Design and fabrication of a cryostat for low temperature mechanical testing for the Mechanical and Materials Engineering group at CERN

    NASA Astrophysics Data System (ADS)

    Aviles Santillana, I.; Betemps, R.; Gerardin, A.; Guinchard, M.; Langeslag, S. A. E.; Sgobba, S.

    2015-12-01

    Mechanical testing of materials at low temperatures is one of the cornerstones of the Mechanical and Materials Engineering (MME) group at CERN. A long tradition of more than 20 years and a unique know - how of such tests has been developed with an 18 kN double-walled cryostat. Large campaigns of material qualification have been carried out and the mechanical behaviour of materials at 4 K has been vastly studied in sub - size samples for projects like LEP, LHC and its experiments. With the aim of assessing the mechanical properties of materials of higher strength and/or issued from heavy gauge products for which testing standardized specimens of larger cross section might be more adapted, a new 100 kN cryostat capable of hosting different shapes of normalized samples has been carefully designed and fabricated inhouse together with the associated tooling and measurement instrumentation. It has been conceived to be able to adapt to different test frames both dynamic and static, which will be of paramount importance for future studies of fracture mechanics at low temperatures. The cryostat features a double-walled vessel consisting of a central cylindrical section with a convex lower end and a flat top end closure. The transmission of the load is guaranteed by a 4 column system and its precise monitoring is assured by an internal load cell positioned next to the sample in the load train. This innovative approach will be discussed together with other nonconventional instrumentation solutions. A validation of the whole system has been carried out, where bending efforts on instrumented samples have been measured. Additionally, dedicated tooling has been fabricated for the device's optimization. The preliminary results obtained confirm an excellent performance of the system and enhance the analysis of materials under extreme conditions with state of the art instrumentation.

  1. NASARC - NUMERICAL ARC SEGMENTATION ALGORITHM FOR A RADIO CONFERENCE

    NASA Technical Reports Server (NTRS)

    Whyte, W. A.

    1994-01-01

    service areas that are sufficiently separated geographically so that co-location or near co-location of their space stations will permit a user-specified downlink performance criterion to be satisfied. Pairwise compatibility between systems is assessed on the basis of the satellite separation required to meet this criterion. NASARC2 examines all groups of compatible administrations with their corresponding arc segments and computes a common predetermined arc. After an orbital slot of sufficient size has been found, NASARC2 calculates the required orbital separation between the critical group and its potential east and west neighbors and determines predetermined arc placement accordingly. NASARC3 updates and extends the feasible orbital locations for predetermined arcs associated with compatible groups of service areas to provide flexibility for rearrangement if necessary. NASARC4 performs rearrangement of predetermined arc segments where rearrangement will provide increased total arc available for subsequent placement of additional predetermined arcs and produces the final output report of the NASARC package. In addition to planning assumed homogeneous systems, NASARC can take into account such factors as rain attenuation, individual antenna parameters, power calculation options, minimum power values, different required carrier-to-interface ratios, variable grouping criteria, and affiliated sets of service areas. The modules allow the baseline assumptions to be modified, some on an individual service area basis. NASARC array dimensions have been structured to fit within the currently available 12MB memory capacity of the International Frequency Registration Board computer facility. NASARC was written in ANSI standard FORTRAN 77 and developed on an AMDAHL 5860 running under the IBM VM operating system. The package requires 8.1MB of central memory. NASARC (version 4.0) was written in 1988. IBM and VM are registered trademarks of International Business Machines. AMDAHL 5860

  2. Cryostatic influence of formvar coatings on sizing of the stabilizer in composite NbTi-Cu superconductors. [for magnets

    NASA Technical Reports Server (NTRS)

    Caspi, S.; Lee, J. Y.; Kim, Y. I.; Frederking, T. H. K.

    1978-01-01

    Often undesirable low energy densities are associated with extreme safety measures (e.g. cryostatic stability) in large superconducting magnets. Therefore, a medium-sized, formvar-coated composite NbTi alloy, Cu-stabilized, has been studied (48 filaments, approximately square cross section about 1/5 cm thickness). Thermal quench behavior (caused by heating) was investigated in various fluid states of He4, including pressurized and superfluid He4. The data obtained support existence of a particular coating thickness ('limiting' thickness) with the property that thermal boundary conditions of uncoated superconductors at a quench are not deteriorated.

  3. Intraoceanic Arc Tectonic and Sedimentary Processes: Translation from Modern Activity to Ancient Records

    NASA Astrophysics Data System (ADS)

    Draut, A. E.; Clift, P. D.

    2013-12-01

    Records of ancient intraoceanic arc activity, now preserved in continental suture zones, are used to reconstruct paleogeography, plate motion, collision and accretion events, and to understand how continental crust is formed, recycled, and maintained through time. However, interpreting tectonic and sedimentary records after arc-continent collision is complicated by preservation of evidence for some processes and loss of evidence for others. We examine what is lost, and what is preserved, in the translation from modern processes to the ancient record of oceanic subduction zones. Composition of accreted arc terranes differs as a function of arc-continent collision geometry. ';Forward-facing' collision can accrete an oceanic arc onto either a passive or an active continental margin, with the arc facing the continent and colliding trench- and forearc-side first. In ';backward-facing' collision, involving two subduction zones with similar polarity, the arc collides backarc-first with an active continental margin. The preservation of evidence for contemporary sedimentary and tectonic arc processes in the geologic record depends greatly on how well the various parts of the arc survive collision and orogeny in each case. Preservation of arc terranes likely is biased towards those that were in tectonic accretion for tens of millions of years before collision, rather than tectonic erosion. The prevalence of tectonic erosion in modern oceanic subduction zones implies that valuable records of arc processes are commonly destroyed even before collision with a continent. Arc systems are most likely to undergo tectonic accretion shortly before forward-facing collision with a continent, and thus most forearc and accretionary-prism material in ancient arc terranes likely is temporally biased toward the final stages of arc activity, when sediment flux to the trench was greatest. Collision geometry and tectonic erosion vs. accretion are important controls on the ultimate survival of

  4. Coordination between Drosophila Arc1 and a specific population of brain neurons regulates organismal fat.

    PubMed

    Mosher, Jeremy; Zhang, Wei; Blumhagen, Rachel Z; D'Alessandro, Angelo; Nemkov, Travis; Hansen, Kirk C; Hesselberth, Jay R; Reis, Tânia

    2015-09-15

    The brain plays a critical yet incompletely understood role in regulating organismal fat. We performed a neuronal silencing screen in Drosophila larvae to identify brain regions required to maintain proper levels of organismal fat. When used to modulate synaptic activity in specific brain regions, the enhancer-trap driver line E347 elevated fat upon neuronal silencing, and decreased fat upon neuronal activation. Unbiased sequencing revealed that Arc1 mRNA levels increase upon E347 activation. We had previously identified Arc1 mutations in a high-fat screen. Here we reveal metabolic changes in Arc1 mutants consistent with a high-fat phenotype and an overall shift toward energy storage. We find that Arc1-expressing cells neighbor E347 neurons, and manipulating E347 synaptic activity alters Arc1 expression patterns. Elevating Arc1 expression in these cells decreased fat, a phenocopy of E347 activation. Finally, loss of Arc1 prevented the lean phenotype caused by E347 activation, suggesting that Arc1 activity is required for E347 control of body fat. Importantly, neither E347 nor Arc1 manipulation altered energy-related behaviors. Our results support a model wherein E347 neurons induce Arc1 in specific neighboring cells to prevent excess fat accumulation. PMID:26209258

  5. Ionospheric composition in SAR-arcs. [Stable Auroral Red Arcs

    NASA Technical Reports Server (NTRS)

    Raitt, W. J.; Schunk, R. W.; Banks, P. M.

    1976-01-01

    Theoretical ion and electron density profiles in the SAR-arc region are calculated using a model of the ionosphere based on the coupled continuity, momentum, and energy equations for O(+), NO(+), and O2(+). It is found that an increase in the reaction O(+) + N2 yields NO(+) + N, which results from enhanced N2 vibrational excitation due to the high electron temperatures found in SAR arcs, can cause a reduction in F-region electron densities by up to a factor of two. The increase in the O(+) + N2 reaction rate is shown to result in a marked change in the ion composition in SAR arcs, with NO(+) being an important ion up to altitudes of about 350 km at night. Since observed electron-density depressions in SAR arcs generally vary between factors of two and seven, it is concluded that the increase in the O(+) + N2 reaction rate cannot account for these depressions by itself.

  6. Arc spot grouping: An entanglement of arc spot cells

    SciTech Connect

    Kajita, Shin; Hwangbo, Dogyun; Ohno, Noriyasu; Tsventoukh, Mikhail M.; Barengolts, Sergey A.

    2014-12-21

    In recent experiments, clear transitions in velocity and trail width of an arc spot initiated on nanostructured tungsten were observed on the boundary of the thick and thin nanostructured layer regions. The velocity of arc spot was significantly decreased on the thick nanostructured region. It was suggested that the grouping decreased the velocity of arc spot. In this study, we try to explain the phenomena using a simple random walk model that has properties of directionality and self-avoidance. And grouping feature was added by installing an attractive force between spot cells with dealing with multi-spots. It was revealed that an entanglement of arc spot cells decreased the spot velocity, and spot cells tend to stamp at the same location many times.

  7. Arc spot grouping: An entanglement of arc spot cells

    NASA Astrophysics Data System (ADS)

    Kajita, Shin; Hwangbo, Dogyun; Ohno, Noriyasu; Tsventoukh, Mikhail M.; Barengolts, Sergey A.

    2014-12-01

    In recent experiments, clear transitions in velocity and trail width of an arc spot initiated on nanostructured tungsten were observed on the boundary of the thick and thin nanostructured layer regions. The velocity of arc spot was significantly decreased on the thick nanostructured region. It was suggested that the grouping decreased the velocity of arc spot. In this study, we try to explain the phenomena using a simple random walk model that has properties of directionality and self-avoidance. And grouping feature was added by installing an attractive force between spot cells with dealing with multi-spots. It was revealed that an entanglement of arc spot cells decreased the spot velocity, and spot cells tend to stamp at the same location many times.

  8. The ALMA Regional Centers (ARC)

    NASA Astrophysics Data System (ADS)

    Andreani, P.; Hibbard, J.; Okumura, S. K.; Braatz, J.

    2011-04-01

    ALMA is an international facility, a partnership between Europe, East Asia, and North America, in cooperation with the Republic of Chile. As such, ALMA will serve a worldwide community of astronomers. To interface with the geographically distributed user community, the partners have established three ALMA Regional Centers, or ARCs. The ARCs provide the primary gateway to ALMA for the user community. The ARCs are staffed by scientists with expertise in radio astronomy and interferometry, and their purpose is to work with the community of astronomers to maximize the scientific productivity of the telescope.

  9. Percussive arc welding apparatus

    DOEpatents

    Hollar, Jr., Donald L.

    2002-01-01

    A percussive arc welding apparatus includes a generally cylindrical actuator body having front and rear end portions and defining an internal recess. The front end of the body includes an opening. A solenoid assembly is provided in the rear end portion in the internal recess of the body, and an actuator shaft assembly is provided in the front end portion in the internal recess of the actuator body. The actuator shaft assembly includes a generally cylindrical actuator block having first and second end portions, and an actuator shaft having a front end extending through the opening in the actuator body, and the rear end connected to the first end portion of the actuator block. The second end portion of the actuator block is in operational engagement with the solenoid shaft by a non-rigid connection to reduce the adverse rebound effects of the actuator shaft. A generally transversely extending pin is rigidly secured to the rear end of the shaft. One end of the pin is received in a slot in the nose housing sleeve to prevent rotation of the actuator shaft during operation of the apparatus.

  10. Arc of opportunity.

    PubMed

    Delaney, Adam Vai

    2011-07-01

    Born in Port Moresby, Papua New Guinea, the author had a 20 year career in diplomacy, political affairs, and development policy analysis at the Pacific Islands Forum, the United Nations in New York; the Prime Minister's Department in Papua New Guinea (PNG) and in the Foreign Ministry of PNG. He has also been involved in theatre for over a decade in PNG, and participated in a three-month program at the Eugene O'Neill Theatre Center in Connecticut, USA. He is currently the Business Development Manager at the Torres Strait Regional Authority (Commonwealth) on Thursday Island. Since 1975 the Australian government's overseas development policy has supported various sectoral programs in its neighbouring countries, in particular Papua New Guinea and the Solomon Islands. The "creative" field has not been prominent in this strategy. While natural resources and the sports sectors have gained much greater attention, in terms of being viable international commercial enterprises, the arts, have remained stagnant. In this paper the need for joint programs genuinely supporting "wellbeing" and promoting social enterprise throughout the "arc of opportunity" is described to harness Melanesian creativity to compete successfully in world-markets, starting with penetration of the largest economy at its door-step: Australia. PMID:21878026