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Sample records for cryogenic helium lep2

  1. Helium cryogenics

    CERN Document Server

    Van Sciver, Steven W

    2012-01-01

    Twenty five years have elapsed since the original publication of Helium Cryogenics. During this time, a considerable amount of research and development involving helium fluids has been carried out culminating in several large-scale projects. Furthermore, the field has matured through these efforts so that there is now a broad engineering base to assist the development of future projects. Helium Cryogenics, 2nd edition brings these advances in helium cryogenics together in an updated form. As in the original edition, the author's approach is to survey the field of cryogenics with emphasis on helium fluids. This approach is more specialized and fundamental than that contained in other cryogenics books, which treat the associated range of cryogenic fluids. As a result, the level of treatment is more advanced and assumes a certain knowledge of fundamental engineering and physics principles, including some quantum mechanics. The goal throughout the work is to bridge the gap between the physics and engineering aspe...

  2. Test of a cryogenic helium pump

    International Nuclear Information System (INIS)

    Lue, J.W.; Miller, J.R.; Walstrom, P.L.; Herz, W.

    1981-01-01

    The design of a cryogenic helium pump for circulating liquid helium in a magnet and the design of a test loop for measuring the pump performance in terms of mass flow vs pump head at various pump speeds are described. A commercial cryogenic helium pump was tested successfully. Despite flaws in the demountable connections, the piston pump itself has performed satisfactorily. A helium pump of this type is suitable for the use of flowing supercritical helium through Internally Cooled Superconductor (ICS) magnets. It has pumped supercritical helium up to 7.5 atm with a pump head up to 2.8 atm. The maximum mass flow rate obtained was about 16 g/s. Performance of the pump was degraded at lower pumping speeds

  3. Cryogenic helium gas convection research

    International Nuclear Information System (INIS)

    Donnelly, R.J.

    1994-10-01

    This is a report prepared by a group interested in doing research in thermal convection using the large scale refrigeration facilities available at the SSC Laboratories (SSCL). The group preparing this report consists of Michael McAshan at SSCL, Robert Behringer at Duke University, Katepalli Sreenivasan at Yale University, Xiao-Zhong Wu at Northern Illinois University and Russell Donnelly at the University of Oregon, who served as Editor for this report. This study reports the research and development opportunities in such a project, the technical requirements and feasibility of its construction and operation, and the costs associated with the needed facilities and support activities. The facility will be a unique national resource for studies of high-Reynolds-number and high-Rayleigh-number and high Rayleigh number turbulence phenomena, and is one of the six items determined as suitable for potential funding through a screening of Expressions of Interest. The proposed facility is possible only because of the advanced cryogenic technology available at the SSCL. Typical scientific issues to be addressed in the facility will be discussed. It devolved during our study, that while the main experiment is still considered to be the thermal convection experiment discussed in our original Expression of Interest, there are now a very substantial set of other, important and fundamental experiments which can be done with the large cryostat proposed for the convection experiment. We believe the facility could provide several decades of front-line research in turbulence, and shall describe why this is so

  4. Helium Inventory Management For LHC Cryogenics

    CERN Document Server

    Pyarali, Maisam

    2017-01-01

    The LHC is a 26.7 km circumference ring lined with superconducting magnets that operate at 1.9 K. These magnets are used to control the trajectory of beams of protons traveling in opposite directions and collide them at various experimental sites across the LHC where their debris is analyzed. The focus of this paper is the cryogenic system that allows the magnets to operate in their superconducting states. It aims to highlight the operating principles of helium refrigeration and liquefaction, with and without nitrogen pre-cooling; discuss the various refrigerators and liquefiers used at CERN for both LHC and Non-LHC applications, with their liquefaction capacities and purposes; and finally to deliberate the management of the LHC inventory and how it contributes to the strategic decision CERN makes regarding the inventory management during the Year-End Technical Stop (YETS), Extended Year-End Technical Stop (EYETS) and long shutdowns.

  5. A cryogenic axial-centrifugal compressor for superfluid helium refrigeration

    CERN Document Server

    Decker, L; Schustr, P; Vins, M; Brunovsky, I; Lebrun, P; Tavian, L

    1997-01-01

    CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance.

  6. CERN: Physics at LEP2

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1994-12-15

    With the LEP2 project pushing ahead to boost CERN's LEP electronpositron collider to higher energy, in February a Workshop on Physics at LEP2 will review the studies for the preparation and interpretation of LEP2 data. The organization of this Workshop and its final report will resemble the 1989 Workshop on Z Physics at LEP1.

  7. CERN: Physics at LEP2

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    With the LEP2 project pushing ahead to boost CERN's LEP electronpositron collider to higher energy, in February a Workshop on Physics at LEP2 will review the studies for the preparation and interpretation of LEP2 data. The organization of this Workshop and its final report will resemble the 1989 Workshop on Z Physics at LEP1

  8. The cryogenic helium cooling system for the Tokamak physics experiment

    International Nuclear Information System (INIS)

    Felker, B.; Slack, D.S.; Wendland, C.R.

    1995-01-01

    The Tokamak Physics Experiment (TPX) will use supercritical helium to cool all the magnets and supply helium to the Vacuum cryopumping subsystem. The heat loads will come from the standard steady state conduction and thermal radiation sources and from the pulsed loads of the nuclear and eddy currents caused by the Central Solenoid Coils and the plasma positioning coils. The operations of the TPX will begin with pulses of up to 1000 seconds in duration every 75 minutes. The helium system utilizes a pulse load leveling scheme to buffer out the effects of the pulse load and maintain a constant cryogenic plant operation. The pulse load leveling scheme utilizes the thermal mass of liquid and gaseous helium stored in a remote dewar to absorb the pulses of the tokamak loads. The mass of the stored helium will buffer out the temperature pulses allowing 5 K helium to be delivered to the magnets throughout the length of the pulse. The temperature of the dewar will remain below 5 K with all the energy of the pulse absorbed. This paper will present the details of the heat load sources, of the pulse load leveling scheme operations, a partial helium schematic, dewar temperature as a function of time, the heat load sources as a function of time and the helium temperature as a function of length along the various components that will be cooled

  9. PIP-II Cryogenic System and the evolution of Superfluid Helium Cryogenic Plant Specifications

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarty, Anindya [Fermilab; Rane, Tejas [Fermilab; Klebaner, Arkadiy [Fermilab

    2017-07-06

    The PIP-II cryogenic system consists of a Superfluid Helium Cryogenic Plant (SHCP) and a Cryogenic Distribution System (CDS) connecting the SHCP to the Superconducting (SC) Linac consisting of 25 cryomodules. The dynamic heat load of the SC cavities for continuous wave (CW) as well as pulsed mode of operation has been listed out. The static heat loads of the cavities along with the CDS have also been discussed. Simulation study has been carried out to compute the supercritical helium (SHe) flow requirements for each cryomodule. Comparison between the flow requirements of the cryomodules for the CW and pulsed modes of operation have also been made. From the total computed heat load and pressure drop values in the CDS, the basic specifications for the SHCP, required for cooling the SC Linac, have evolved.

  10. Online helium inventory monitoring of JLab cryogenic systems

    Science.gov (United States)

    Hasan, N.; Knudsen, P.; Wright, M.

    2017-12-01

    There are five cryogenic plants at Jefferson Lab which support the LINAC, experiment hall end-stations and test facility. The majority of JLab’s helium inventory, which is around 15 tons, is allocated in the LINAC cryo-modules, with the majority of the balance of helium distributed at the cryogenic-plant level mainly as stored gas and liquid for stable operation. Due to the organic evolution of the five plants and independent actions within the experiment halls, the traditional inventory management strategy suffers from rapid identification of potential leaks. This can easily result in losses many times higher than the normally accepted (average) loss rate. A real-time program to quickly identify potential excessive leakage was developed and tested. This program was written in MATLAB© for portability, easy diagnostics and modification. It interfaces directly with EPICS to access the cryogenic system state, and with and NIST REFPROP© for real fluid properties. This program was validated against the actual helium offloaded into the system. The present paper outlines the details of the inventory monitoring program, its validation and a sample of the achieved results.

  11. Design concept of cryogenic falling liquid film helium separator

    International Nuclear Information System (INIS)

    Kinoshita, M.; Yamanishi, T.; Bartlit, J.R.; Sherman, R.H.

    1986-01-01

    A design concept is developed for a cryogenic falling liquid film helium separator by clarifying the differences between this process and a cryogenic distillation column. The process characteristics are greatly improved by the idea of adding an H 2 gas flow to a point near the upper end of the packed section. The flow rate of tritium lost from the top is kept extremely low with an adequately short packed section, and the column pressure is reduced to 1 atm. The addition causes no appreciable increase in the protium percentage (approx. =1%) in the bottom liquid flow. A design procedure applying the Colburn-Hougen method is proposed for determining specifications of the refrigerated section. It is shown that the presence of noncondensible helium requires a significantly larger heat transfer area mainly because the mass transfer resistance increases enormously as the condensation of hydrogen isotopes proceeds. Control schemes are also proposed: The tritium concentration in the top gas is controlled by the H 2 gas flow rate. The pressure rise caused by an increase of the helium percentage within the refrigerated section, which cannot readily be eliminated by changing input specifications of the refrigerant gas, is avoided by increasing the top gas flow rate to release more helium from the top

  12. A High Reliability Gas-driven Helium Cryogenic Centrifugal Compressor

    CERN Document Server

    Bonneton, M; Gistau-Baguer, Guy M; Turcat, F; Viennot, P

    1998-01-01

    A helium cryogenic compressor was developed and tested in real conditions in 1996. The achieved objective was to compress 0.018 kg/s Helium at 4 K @ 1000 Pa (10 mbar) up to 3000 Pa (30 mbar). This project was an opportunity to develop and test an interesting new concept in view of future needs. The main features of this new specific technology are described. Particular attention is paid to the gas bearing supported rotor and to the pneumatic driver. Trade off between existing technologies and the present work are presented with special stress on the bearing system and the driver. The advantages are discussed, essentially focused on life time and high reliability without maintenance as well as non pollution characteristic. Practical operational modes are also described together with the experimental performances of the compressor. The article concludes with a brief outlook of future work.

  13. Cryogenic recovery analysis of forced flow supercritical helium cooled superconductors

    International Nuclear Information System (INIS)

    Lee, A.Y.

    1977-08-01

    A coupled heat conduction and fluid flow method of solution was presented for cryogenic stability analysis of cabled composite superconductors of large scale magnetic coils. The coils are cooled by forced flow supercritical helium in parallel flow channels. The coolant flow reduction in one of the channels during the spontaneous recovery transient, after the conductor undergoes a transition from superconducting to resistive, necessitates a parallel channel analysis. A way to simulate the parallel channel analysis is described to calculate the initial channel inlet flow rate required for recovery after a given amount of heat is deposited. The recovery capability of a NbTi plus copper composite superconductor design is analyzed and the results presented. If the hydraulics of the coolant flow is neglected in the recovery analysis, the recovery capability of the superconductor will be over-predicted

  14. Cryogenics

    International Nuclear Information System (INIS)

    Fradkov, A.B.

    1991-01-01

    The application of cryogenics in various areas of science and technology is related in a popular way. Utilization of cryogenics in the following production processes is described: separation of air, gas mixtures; production of helium; separation of hydrogen isotopes; production of deuterium. Applications of cryogenics in refrigerating engineering, superconductivity and high-energy physics, controlled thermonuclear fusion, superconducting electric motors and electric energy storages are considered

  15. Gaseous Helium storage and management in the cryogenic system for the LHC

    CERN Document Server

    Barranco-Luque, M

    2000-01-01

    The Large Hadron Collider (LHC) is presently under construction at CERN. Its main components are superconducting magnets which will operate in superfluid helium requiring cryogenics on a length of about 24 km around the machine ring with a total helium inventory of about 100 tonnes. As no permanent liquid helium storage is foreseen and for reasons of investment costs, only half of the total helium content can be stored in gaseous form in medium pressure vessels. During the LHC operation part of these vessels will be used as helium buffer in the case of multiple magnet quenches. This paper describes the storage, distribution and management of the helium, the layout and the connection to the surface and underground equipment of the cryogenic system.

  16. Electroweak physics at LEP2

    CERN Document Server

    Hemingway, Richard J

    2002-01-01

    On 2 November 2000 the LEP machine was finally closed after 12 years of glorious running. With the 4 operating detectors, ALEPH, DELPHI, L3, and OPAL, an enormous wealth of new data at the highest centre- of-mass energies has been recorded. These lectures will focus on aspects of electroweak physics within the energy span of LEP2, namely 130-209 GeV. All current data are in very good agreement with the electroweak standard model. (50 refs).

  17. Colour Reconnection at LEP2

    CERN Document Server

    Nandakumar, Raja

    2001-01-01

    Colour reconnection is the final state interaction between quarks from different sources. It is not yet fully understood and is a source of systematic error for W-boson mass and width measurements in hadronic \\WW decays at LEP2. The methods of measuring this effect and the results of the 4 LEP experiments at $183\\gev\\leq\\rts\\leq 202\\gev$ will be presented.

  18. Cryogenic filter method produces super-pure helium and helium isotopes

    Science.gov (United States)

    Hildebrandt, A. F.

    1964-01-01

    Helium is purified when cooled in a low pressure environment until it becomes superfluid. The liquid helium is then filtered through iron oxide particles. Heating, cooling and filtering processes continue until the purified liquid helium is heated to a gas.

  19. Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

    Energy Technology Data Exchange (ETDEWEB)

    Chu, X. X.; Zhang, D. X.; Qian, Y.; Liu, W. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800 (China); Zhang, M. M.; Xu, D. [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China)

    2014-01-29

    In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H{sub 2} from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H{sub 2} in helium recycle gas are less than 1 ppb.

  20. Cryogenic tunable microwave cavity at 13GHz for hyperfine spectroscopy of antiprotonic helium

    International Nuclear Information System (INIS)

    Sakaguchi, J.; Gilg, H.; Hayano, R.S.; Ishikawa, T.; Suzuki, K.; Widmann, E.; Yamaguchi, H.; Caspers, F.; Eades, J.; Hori, M.; Barna, D.; Horvath, D.; Juhasz, B.; Torii, H.A.; Yamazaki, T.

    2004-01-01

    For the precise measurement of the hyperfine structure of antiprotonic helium, microwave radiation of 12.9GHz frequency is needed, tunable over +/-100MHz. A cylindrical microwave cavity is used whose front and rear faces are meshed to allow the antiprotons and laser beams to enter. The cavity is embedded in a cryogenic helium gas target. Frequency tuning of ∼300MHz with Q values of 2700-3000 was achieved using over-coupling and an external triple stub tuner. We also present Monte-Carlo simulations of the stopping distribution of antiprotons in the low-density helium gas using the GEANT4 package with modified energy loss routines

  1. Metrological analysis of a virtual flowmeter-based transducer for cryogenic helium

    Energy Technology Data Exchange (ETDEWEB)

    Arpaia, P., E-mail: pasquale.arpaia@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Girone, M., E-mail: mario.girone@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Department of Engineering, University of Sannio, Benevento (Italy); Liccardo, A., E-mail: annalisa.liccardo@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Pezzetti, M., E-mail: marco.pezzetti@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Piccinelli, F., E-mail: fabio.piccinelli@cern.ch [Department of Mechanical Engineering, University of Brescia, Brescia (Italy)

    2015-12-15

    The metrological performance of a virtual flowmeter-based transducer for monitoring helium under cryogenic conditions is assessed. At this aim, an uncertainty model of the transducer, mainly based on a valve model, exploiting finite-element approach, and a virtual flowmeter model, based on the Sereg-Schlumberger method, are presented. The models are validated experimentally on a case study for helium monitoring in cryogenic systems at the European Organization for Nuclear Research (CERN). The impact of uncertainty sources on the transducer metrological performance is assessed by a sensitivity analysis, based on statistical experiment design and analysis of variance. In this way, the uncertainty sources most influencing metrological performance of the transducer are singled out over the input range as a whole, at varying operating and setting conditions. This analysis turns out to be important for CERN cryogenics operation because the metrological design of the transducer is validated, and its components and working conditions with critical specifications for future improvements are identified.

  2. Dynamics of cold helium flow inside a cryoline used for large cryogenic distribution system

    International Nuclear Information System (INIS)

    Kumar, Uday; Jadon, Mohit; Choukekar, Ketan; Shukla, Vinit; Patel, Pratik; Kapoor, Himanshu; Shah, Nitin; Muralidhara, Srinivasa; Sarkar, Biswanath

    2015-01-01

    The Cryolines, which by definition transfers cryogens from the source, normally a cryogenic plant, to several systems requiring cooling at cryogenic temperature to the level of 4 K and 80 K. The operations of cryolines are normally assumed to be steady state following a cool down from room temperature to the cryogenic temperature. It is to be noted that in a distributed cryogenic system, especially in a nuclear facility such as ITER having confinement definition due to the regulatory requirements, do also attract the attention in the system design that the release from safety valves cannot be allowed inside a building. Therefore, all safety valves need to be discharged inside a confined space, which is a specific space requiring fulfillment of definition for a cryogenic line. The specificity in such cases is that such cryogenic lines will realize dynamic conditions for each release of safety valves or a combination of safety valves in terms of pressure, temperature and flow, leading to unexpected failures. Such operating scenarios also lead to serious impact on fatigue with a question mark on the reliability. Therefore, one can define such cryolines as Relief Collection Header (RCH) which collects discharged helium and transport it to the appropriate place as defined in the system design. The discharges of cold helium from safety relief discharge ports of equipment can result into significantly unsteady and compressible flow in RCH. The proper design of the RCH has to be supported by detailed dynamic of expected flow phenomena for specific cases. The paper presents the dynamics of cold helium flow inside the typical RCH that has been performed to investigate the variation in flow parameters (pressure, temperature, velocity and density) along the axis of RCH and predictions on its reliability. (author)

  3. ELECTRON ENERGY DECAY IN HELIUM AFTERGLOW PLASMAS AT CRYOGENIC TEMPERATURES

    Energy Technology Data Exchange (ETDEWEB)

    Goldan, P. D.; Cahn, J. H.; Goldstein, L.

    1963-10-15

    Studies of decaying afterglow plasmas in helium were ined near 4 deg K by immersion in a liquid helium bath. By means of a Maser Radiometer System, the electron temperature was followed below 200 deg K. Guided microwave propagation and wave interaction techniques premit determination of election number density and collision frequencies for momentum transfer. Electron temperature decay rates of the order of 150 mu sec/p(mm Hg alpha 4.2 deg K) were found. Since thermal relaxation by elastic collisions should be some two orders of magnitude faster than this, the electrons appear to be in quasiequilibrium with a slowly decaying internal heating source. Correlation of the expected decay rates of singlet metastable helium atoms with the electron temperature decay gives good agreement with the present experiment. (auth)

  4. Cryogenics

    International Nuclear Information System (INIS)

    Shukla, R.K.

    1990-01-01

    Cryogenics refers to the coldest area known in nature. This temperature range has an upper limit arbitrarily defined as -100 degrees C (-250 degrees C by some) and a lower limit of absolute zero. These limits separate it from the temperature range generally used in refrigerating engineering. One important application of cryogenics is the separation ad purification of air into its various components (oxygen, nitrogen, argon, and the rare gases). Other important developments have been the large-scale production of liquid hydrogen; helium extraction from natural gas; storage and transport of liquefied gases such as oxygen, argon, nitrogen, helium, neon, xenon, and hydrogen; liquefaction of natural gas for ocean transport and peak shaving; and many new types of cryogenic refrigeration devices. This paper introduces the topic of cryogenic engineering. Cryogenic processes generally range from ambient conditions to the boiling point of the cryogenic fluid. Cryogenic cycles also incorporate two or more pressure levels. These properties must also cover the vapor, vapor-liquid, and sometimes the solid regions. Therefore, the physical properties of fluids over a great range of temperatures and pressures must be known. Solubility of contaminants must be known in order to design for their removal. The main physical properties for design purposes are those usually used in unit operations, such as fluid flow, heat transfer, and the like, in addition to those directly related to the Joule-Thomson effect and expansion work. Properties such as density, viscosity, thermal conductivity, heat capacity, enthalpy, entropy, vapor pressure, and vapor-liquid equilibriums are generally obtained in graphical, tabular, or equation form, as a function of temperature and pressure

  5. Operational experience with double acting piston pumps for cryogenic helium and nitrogen

    International Nuclear Information System (INIS)

    Vosswinkel, F.

    1978-01-01

    The design of a high efficiency double acting piston pump suitable for pumping liquefied gases at cryogenic temperatures for cable cooling, is reported. The pump has proved flexible, reliable and efficient in operation. The plunger-type pumps can be used for filling cryostats or dewars with liquid helium or nitrogen from a pressure free or pressurized storage vessel, or as circulators for subcooled, saturated and/or supercritical helium in large scale cooling experiments. Flow rates of up to 17 g/s, maximum operating pressure of 600 kPa absolute and maximum differential pressure of approximately 100 kPa are obtained. (UK)

  6. EXERGY ANALYSIS OF THE CRYOGENIC HELIUM DISTRIBUTION SYSTEM FOR THE LARGE HADRON COLLIDER (LHC)

    International Nuclear Information System (INIS)

    Claudet, S.; Lebrun, Ph.; Tavian, L.; Wagner, U.

    2010-01-01

    The Large Hadron Collider (LHC) at CERN features the world's largest helium cryogenic system, spreading over the 26.7 km circumference of the superconducting accelerator. With a total equivalent capacity of 145 kW at 4.5 K including 18 kW at 1.8 K, the LHC refrigerators produce an unprecedented exergetic load, which must be distributed efficiently to the magnets in the tunnel over the 3.3 km length of each of the eight independent sectors of the machine. We recall the main features of the LHC cryogenic helium distribution system at different temperature levels and present its exergy analysis, thus enabling to qualify second-principle efficiency and identify main remaining sources of irreversibility.

  7. Exergy Analysis of the Cryogenic Helium Distribution System for the Large Hadron Collider (LHC)

    CERN Document Server

    Claudet, S; Tavian, L; Wagner, U

    2010-01-01

    The Large Hadron Collider (LHC) at CERN features the world’s largest helium cryogenic system, spreading over the 26.7 km circumference of the superconducting accelerator. With a total equivalent capacity of 145 kW at 4.5 K including 18 kW at 1.8 K, the LHC refrigerators produce an unprecedented exergetic load, which must be distributed efficiently to the magnets in the tunnel over the 3.3 km length of each of the eight independent sectors of the machine. We recall the main features of the LHC cryogenic helium distribution system at different temperature levels and present its exergy analysis, thus enabling to qualify second-principle efficiency and identify main remaining sources of irreversibility..

  8. Economics of Large Helium Cryogenic Systems experience from Recent Projects at CERN

    CERN Document Server

    Claudet, S; Lebrun, P; Tavian, L; Wagner, U

    1999-01-01

    Large projects based on applied superconductivity, such as particle accelerators, tokamaks or SMES, require powerful and complex helium cryogenic systems, the cost of which represents a significant, if not dominant fraction of the total capital and operational expenditure. It is therefore important to establish guidelines and scaling laws for costing such systems, based on synthetic estimators of their size and performance. Although such data has already been published for many years, the experience recently gathered at CERN with the LEP and LHC projects, which have de facto turned the laboratory into a major world cryogenic center, can be exploited to update this information and broaden the range of application of the scaling laws. We report on the economics of 4.5 K and 1.8 K refrigeration, cryogen distribution and storage systems, and indicate paths towards their cost-to-performance optimisation.

  9. Experimental Characterization of Cryogenic Helium Pulsating Heat Pipes

    Science.gov (United States)

    Fonseca Flores, Luis Diego

    This study was inspired to investigate an alternative cooling system using a helium-based pulsating heat pipes (PHP), for low temperature superconducting magnets in MRI systems. In addition, the same approach can be used for exploring other low temperature applications such as cooling space instrumentation. The advantages of PHP for transferring heat and smoothing temperature profiles in various room temperature applications have been explored for the past 20 years. An experimental apparatus has been designed, fabricated and operated and is primarily composed of an evaporator and a condenser; in which both are thermally connected by a closed loop capillary tubing. The main goal is to measure the heat transfer properties of this device using helium as the working fluid. The evaporator end of the PHP is comprised of a copper winding in which heat loads up to 10 watts are generated, while the condenser is isothermal and can reach 4.2 K at 1 W via a two stage Sumitomo RDK408A2 GM cryocooler. Various experimental design features are highlighted. Additionally, the thermal performance for the presented design remained unchanged when increasing the adiabatic length from 300 mm to 1000 mm. Finally a spring mass damper model has been developed and proven to predict well the experimental data, such models should be used as tool to design and manufacturer PHP prototypes.

  10. Thermal analysis of a coaxial helium panel of a cryogenic vacuum pump for advanced divertor of DIII-D tokamak

    International Nuclear Information System (INIS)

    Baxi, C.B.; Langhorn, A.; Schaubel, K.; Smith, J.

    1991-08-01

    It is planned to install a 50,000 1/s cryogenic pump for particle removal in the D3-D tokamak. A critical component of this cryogenic pump will be a helium panel which has to be maintained at a liquid helium temperature. The outer surface area of the helium panel has an area of 1 m 2 and consists of a 2.5 cm diameter, 10 m long tube. From design considerations, a coaxial geometry is preferable since it requires a minimum number of welds. However, the coaxial geometry also results in a counter flow heat exchanger arrangement, where the outgoing warm fluid will exchange heat with incoming cold fluid. This is of concern since the helium panel must be cooled from liquid nitrogen temperature to liquid helium temperature in less than 5 minutes for successful operation of the cryogenic pump. In order to analyze the thermal performance of the coaxial helium panel, a finite difference computer model of the geometry was prepared. The governing equations took into account axial as well as radial conduction through the tube walls. The variation of thermal properties was modeled. The results of the analysis showed that although the coaxial geometry behaves like a counter flow heat exchanger, within the operating range of the cryogenic pump a rapid cooldown of the helium panel from liquid nitrogen temperature to the operating temperature is feasible. A prototypical experiment was also performed at General Atomics (GA) which verified the concept and the analysis. 4 refs., 8 figs

  11. Dynamic modeling and simulation of the superconducting super collider cryogenic helium system

    International Nuclear Information System (INIS)

    Hartzog, D.G.; Fox, V.G.; Mathias, P.M.; Nahmias, D.; McAshan, M.; Carcagno, R.

    1989-01-01

    To study the operation of the Superconducting Super Collider (SSC) cryogenic system during transient operating conditions, they have developed and programmed in FORTRAN, a time-dependent, nonlinear, homogeneous, lumped-parameter simulation model of the SSC cryogenic system. This dynamic simulator has a modular structure so that process flowsheet modifications can be easily accommodated with minimal recoding. It uses the LSODES integration package to advance the solution in time. For helium properties it uses Air Products implementation of the standard thermodynamic model developed by the NBS. Two additional simplified helium thermodynamic models developed by Air Products are available as options to reduce computation time. To facilitate the interpretation of output, they have linked the simulator to the speakeasy conversational language. The authors present a flowsheet of the process simulated, and the material and energy balances used in the engineering models. They then show simulation results for three transient operating scenarios: startup of the refrigeration system from standby to full load; the loss of 4K refrigeration caused by the tripping of one of two parallel compressors in a sector; and a full-field quench of a single magnet half-cell. They discuss the response of the fluid within the cryogenic circuits during these scenarios. 14 refs., 19 figs., 2 tabs

  12. Numerical investigation of potential stratification caused by a cryogenic helium spill inside a tunnel

    Science.gov (United States)

    Sinclair, Cameron; Malecha, Ziemowit; Jedrusyna, Artur

    2018-04-01

    The sudden release of cryogenic fluid into an accelerator tunnel can pose a significant health and safety risk. For this reason, it is important to evaluate the consequences of such a spill. Previous publications concentrated on either Oxygen Deficiency Hazard or the evaluation of mathematical models using experimental data. No studies to date have focussed on the influence of cryogen inlet conditions on flow development. In this paper, the stratification behaviour of low-temperature helium released into an air-filled accelerator tunnel is investigated for varying helium inlet diameters. A numerical model was constructed using the OpenFOAM Toolbox of a generalised 3D geometry, with similar hydraulic characteristics to the CERN and SLAC tunnels. This model has been validated against published experimental and numerical data. A dimensionless parameter, based on Bakke number, was then determined for the onset of stratification, taking into account the helium inlet diameter; a dimensionless parameter for the degree of stratification was also employed. The simulated flow behaviour is described in terms of these dimensionless parameters, as well as the temperature and oxygen concentration at various heights throughout the tunnel.

  13. Cryogenic thermometer calibration system using a helium cooling loop and a temperature controller [for LHC magnets

    CERN Document Server

    Chanzy, E; Thermeau, J P; Bühler, S; Joly, C; Casas-Cubillos, J; Balle, C

    1998-01-01

    The IPN-Orsay and CERN are designing in close collaboration a fully automated cryogenic thermometer calibration facility which will calibrate in 3 years 10,000 cryogenic thermometers required for the Large Hadron Collider (LHC) operation. A reduced-scale model of the calibration facility has been developed, which enables the calibration of ten thermometers by comparison with two rhodium-iron standard thermometers in the 1.8 K to 300 K temperature range under vacuum conditions. The particular design, based on a helium cooling loop and an electrical temperature controller, gives good dynamic performances. This paper describes the experimental set-up and the data acquisition system. Results of experimental runs are also presented along with the estimated global accuracy for the calibration. (3 refs).

  14. Revision of the design model for a cryogenic falling liquid film helium separator

    International Nuclear Information System (INIS)

    Kinoshita, Masahiro; Bartlit, J.R.; Sherman, R.H.

    1983-05-01

    The present paper reports revision of the design model previously developed by the authors for the cryogenic falling liquid film helium separator. The revised design procedure is composed of three steps : 1) calculation of distributions of phase flow rates, temperature and phase compositions within the refrigerated section and the packed section ; 2) calculation of more detailed distributions of these variables within the refrigerated section ; and 3) estimation of column dimensions and determination of operating conditions. It is assumed that the vacant refrigerated section has two theoretical stages for hydrogen isotope separation. The mixture within the refrigerated section is considered in step 2) as two component system of He-HD. (author)

  15. Quantum chromodynamics studies at LEP2

    Indian Academy of Sciences (India)

    swaban swaban

    Studies of the annihilation process at LEP2 have given rise to results on jet rate, event ..... The electroweak theory explain the data at all these energies. .... like (a) smooth suppression of hadron-like and point-like 7 interaction, (b) dual parton.

  16. W boson physics at LEP2

    International Nuclear Information System (INIS)

    Tonazzo, A.

    2000-01-01

    The precision study of W boson properties is one of the most important goals of the LEP2 physics programme. This paper provides an overview of the measurements performed by the four LEP experiments, with particular emphasis on the extraction of the W mass. A review of the results obtained with the data collected until 1999 is also presented

  17. The Local Helium Compound Transfer Lines for the Large Hadron Collider Cryogenic System

    CERN Document Server

    Parente, C; Munday, A; Wiggins, P

    2006-01-01

    The cryogenic system for the Large Hadron Collider (LHC) under construction at CERN will include twelve new local helium transfer lines distributed among five LHC points in underground caverns. These lines, being manufactured and installed by industry, will connect the cold boxes of the 4.5-K refrigerators and the 1.8-K refrigeration units to the cryogenic interconnection boxes. The lines have a maximum of 30-m length and may possess either small or large re-distribution units to allow connection to the interface ports. Due to space restrictions the lines may have complex routings and require several elbowed sections. The lines consist of a vacuum jacket, a thermal shield and either three or four helium process pipes. Specific internal and external supporting and compensation systems were designed for each line to allow for thermal contraction of the process pipes (or vacuum jacket, in case of a break in the insulation vacuum) and to minimise the forces applied to the interface equipment. Whenever possible, f...

  18. Commissioning of the helium cryogenic system for the HIE- ISOLDE accelerator upgrade at CERN

    International Nuclear Information System (INIS)

    Delruelle, N; Inglese, V; Leclercq, Y; Pirotte, O; Williams, L

    2015-01-01

    The High Intensity and Energy ISOLDE (HIE-ISOLDE) project is a major upgrade of the existing ISOLDE and REX-ISOLDE facilities at CERN. The most significant improvement will come from replacing the existing REX accelerating structure by a superconducting linear accelerator (SC linac) composed ultimately of six cryo-modules installed in series, each containing superconducting RF cavities and solenoids operated at 4.5 K. In order to provide the cooling capacity at all temperature levels between 300 K and 4.5 K for the six cryo-modules, an existing helium refrigerator, manufactured in 1986 and previously used to cool the ALEPH magnet during LEP operation from 1989 to 2000, has been refurbished, reinstalled and recommissioned in a dedicated building located next to the HIE-ISOLDE experimental hall. This helium refrigerator has been connected to a new cryogenic distribution line, consisting of a 30-meter long vacuum-insulated transfer line, a 2000-liter storage dewar and six interconnecting valve boxes, one for each cryo-module. This paper describes the whole cryogenic system and presents the commissioning results including the preliminary operation at 4.5 K of the first cryo- module in the experimental hall. (paper)

  19. The LEP2 superconducting RF system

    CERN Document Server

    Butterworth, A; Brunner, O; Ciapala, Edmond; Frischholz, Hans; Geschonke, Günther; Peschardt, E; Sladen, J

    2008-01-01

    The upgrade of LEP2 energy to beyond the W boson production threshold required the progressive installation of a completely new radio-frequency (RF) accelerating system. The new system used superconducting (SC) cavities, which complemented and partially replaced the original LEP1 RF system based on conventional copper cavity technology. The final system consisted of 56 copper and 288 SC cavities and provided a peak acceleration of more than 3600 MV/turn. This paper describes the main elements of the SC system and reviews the 5 years of LEP2 operation at gradients well beyond the design specification. Also presented are some of the main performance limitations and problems encountered together with the various solutions and procedures found to eliminate them or reduce their effects.

  20. Commissioning of the helium cryogenic system for the HIE- ISOLDE accelerator upgrade at CERN

    CERN Document Server

    Delruelle, N; Leclercq, Y; Pirotte, O; Williams, L

    2015-01-01

    The High Intensity and Energy ISOLDE (HIE-ISOLDE) project is a major upgrade of the existing ISOLDE and REX-ISOLDE facilities at CERN. The most significant improvement will come from replacing the existing REX accelerating structure by a superconducting linear accelerator (SC linac) composed ultimately of six cryo-modules installed in series, each containing superconducting RF cavities and solenoids operated at 4.5 K. In order to provide the cooling capacity at all temperature levels between 300 K and 4.5 K for the six cryo-modules, an existing helium refrigerator, manufactured in 1986 and previously used to cool the ALEPH magnet during LEP operation from 1989 to 2000, has been refurbished, reinstalled and recommissioned in a dedicated building located next to the HIE-ISOLDE experimental hall. This helium refrigerator has been connected to a new cryogenic distribution line, consisting of a 30-meter long vacuum-insulated transfer line, a 2000-liter storage dewar and six interconnecting valve boxes, one for eac...

  1. A 6 kW at 4.5 K helium refrigerator for CERN's Cryogenic Test Station

    International Nuclear Information System (INIS)

    Gistau, G.M.; Bonneton, M.

    1994-01-01

    For purposes of testing the present LEP superconducting resonant cavities and the future LHC magnets, CERN built a test station the cryogenic power of which is presently supplied by a dedicated 6 kW at 4.5 K helium refrigerator. The thermodynamic cycle is discussed and special emphasis is put on a new cryogenic expansion turbine operating in the liquid phase. Information is given about: the cycle screw compressors' performances, the general performance of the refrigerator, the expected efficiency enhancement due to the liquid turbine, an off-design turn down operation

  2. Physics at LEP2. Vol. 2

    International Nuclear Information System (INIS)

    Altarelli, G.; Sjoestrand, T.; Zwirner, F.

    1995-01-01

    This is final report of the Workshop on Physics at LEP2, held at CERN during 1995. The first part of vol. 1 is devoted to aspects of machine physics of particular relevance to experiments, including the energy, luminosity and interaction regions, as well as the measurement of beam energy. The second part of vol. 1 is a relatively concise, but fairly complete, handbook on the physics of e + e - annihilation above the WW threshold and up to √s∼200 GeV. It contains discussions on WW cross-sections and distributions, W mass determination, Standard Model processes, QCD and gamma-gamma physics, as well as aspects of discovery physics, such as Higgs, new particle searches, triple gauge boson couplings and Z'. The second volume contains a review of the existing Monte Carlo generators for LEP2 physics. These include generators for WW physics, QCD and gamma-gamma processes, Bhabha scattering and discovery physics. A special effort was made to co-ordinate the different parts, with a view to achieving a systematic and balanced review of the subject, rather than just publishing a collection of separate contributions. (orig.)

  3. Physics at LEP2. Vol. 1

    International Nuclear Information System (INIS)

    Altarelli, G.; Sjoestrand, T.; Zwirner, F.

    1996-01-01

    This is the final report of the Workshop on Physics at LEP2, held at CERN during 1995. The first part of vol. 1 is devoted to aspects of machine physics of particular relevance to experiments, including the energy, luminosity and interaction regions, as well as the measurement of beam energy. The second part of vol. 1 is a relatively concise, but fairly complete, handbook on the physics of e + e - annihilation above the WW threshold and up to √s∼200 GeV. It contains discussions on WW cross-sections and distributions, W mass determination, Standard Model processes, QCD and gamma-gamma physics, as well as aspects of discovery physics, such as Higgs, new particle searches, triple gauge boson couplings and Z'. The second volume contains a review of the existing Monte Carlo generators for LEP2 physics. These include generators for WW physics, QCD and gamma-gamma processes, Bhabha scattering and discovery physics. A special effort was made to co-ordinate the different parts, with a view to achieving a systematic and balanced review of the subject, rather than just publishing a collection of separate contributions. (orig.)

  4. Physics at LEP2. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Altarelli, G [ed.; Sjoestrand, T [ed.; Zwirner, F [ed.

    1995-02-19

    This is final report of the Workshop on Physics at LEP2, held at CERN during 1995. The first part of vol. 1 is devoted to aspects of machine physics of particular relevance to experiments, including the energy, luminosity and interaction regions, as well as the measurement of beam energy. The second part of vol. 1 is a relatively concise, but fairly complete, handbook on the physics of e{sup +}e{sup -} annihilation above the WW threshold and up to {radical}s{approx}200 GeV. It contains discussions on WW cross-sections and distributions, W mass determination, Standard Model processes, QCD and gamma-gamma physics, as well as aspects of discovery physics, such as Higgs, new particle searches, triple gauge boson couplings and Z`. The second volume contains a review of the existing Monte Carlo generators for LEP2 physics. These include generators for WW physics, QCD and gamma-gamma processes, Bhabha scattering and discovery physics. A special effort was made to co-ordinate the different parts, with a view to achieving a systematic and balanced review of the subject, rather than just publishing a collection of separate contributions. (orig.).

  5. Successful vitrification of bovine immature oocyte using liquid helium instead of liquid nitrogen as cryogenic liquid.

    Science.gov (United States)

    Yu, Xue-Li; Xu, Ya-Kun; Wu, Hua; Guo, Xian-Fei; Li, Xiao-Xia; Han, Wen-Xia; Li, Ying-Hua

    2016-04-01

    The objectives of this study were to compare the effectiveness of liquid helium (LHe) and liquid nitrogen (LN2) as cryogenic liquid for vitrification of bovine immature oocytes with open-pulled straw (OPS) system and determine the optimal cryoprotectant concentration of LHe vitrification. Cumulus oocyte complexes were divided into three groups, namely, untreated group (control), LN2 vitrified with OPS group, and LHe vitrified with OPS group. Oocyte survival was assessed by morphology, nuclear maturation, and developmental capability. Results indicated that the rates of normal morphology, maturation, cleavage, and blastocyst (89.3%, 52.8%, 42.7%, and 10.1%, respectively) in the LHe-vitrified group were all higher than those (79.3%, 43.4%, 34.1%, and 4.7%) in the LN2-vitrified group (P 0.05). The maturation rate of the EDS35 group (65.0%) was higher than those of the EDS30 (51.3%), EDS40 (50.1%), EDS45 (52.1%), and EDS50 groups (36.9%; P liquid for vitrification of bovine immature oocytes, and it is more efficient than LN2-vitrified oocytes in terms of blastocyst production. EDS35 was the optimal cryoprotectant agent combination for LHe vitrification in this study. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Experimental evidence of the statistical intermittency in a cryogenic turbulent jet of normal and superfluid Helium

    International Nuclear Information System (INIS)

    Duri, D.

    2012-01-01

    This experimental work is focused on the statistical study of the high Reynolds number turbulent velocity field in an inertially driven liquid helium axis-symmetric round jet at temperatures above and below the lambda transition (between 2.3 K and 1.78 K) in a cryogenic wind tunnel. The possibility to finely tune the fluid temperature allows us to perform a comparative study of the quantum He II turbulence within the classical framework of the Kolmogorov turbulent cascade in order to have a better understanding of the energy cascade process in a superfluid. In particular we focused our attention on the intermittency phenomena, in both He I and He II phases, by measuring the high order statistics of the longitudinal velocity increments by means of the flatness and the skewness statistical estimators. A first phase consisted in developing the cryogenic facility, a closed loop pressurized and temperature regulated wind tunnel, and adapting the classic hot-wire anemometry technique in order to be able to work in such a challenging low temperature environment. A detailed calibration procedure of the fully developed turbulent flow was the carried out at 2.3 K at Reynolds numbers based on the Taylor length scale up to 2600 in order to qualify our testing set-up and to identify possible facility-related spurious phenomena. This procedure showed that the statistical properties of the longitudinal velocity increments are in good agreement with respect to previous results. By further reducing the temperature of the working fluid (at a constant pressure) below the lambda point down to 1.78 K local velocity measurements were performed at different superfluid density fractions. The results show a classic behaviour of the He II energy cascade at large scales while, at smaller scales, a deviation has been observed. The occurrence of this phenomenon, which requires further investigation and modelling, is highlighted by the observed changing sign of the third order structure

  7. Study on cryogenic adsorption capability of trace nitrogen and methane by activated carbon for cooIant helium purification

    International Nuclear Information System (INIS)

    Chang Hua; Wu Zongxin

    2014-01-01

    A fixed-bed apparatus with dynamic two-route proportional gas mixing system was designed to investigate the cryogenic adsorption behavior of nitrogen and methane on activated carbon for designing the helium purification system of high-temperature gas-cooled reactors (HTGR). With helium as carrier gas and at the impurity partial pressure of tens Pa, experiments were performed at near atmospheric pressure and by dynamic column breakthrough method at -196°C. The breakthrough curves and desorption curves were measured. By analyzing the breakthrough curve, both the equilibrium adsorption capacity and the kinetic adsorption capacity at breakthrough point were determined. Based on mass-transfer zone model, the experimental breakthrough curves were analyzed. (author)

  8. Practical-scale tests of cryogenic molecular sieve for separating low-concentration hydrogen isotopes from helium

    International Nuclear Information System (INIS)

    Willms, R.S.; Taylor, D.J.; Enoeda, Mikio; Okuno, Kenji

    1994-01-01

    Earlier bench-scale work at the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory examined a number of adsorbents for their suitability for separating low-concentration hydrogen (no tritium) from helium. One of the effective adsorbents was Linde 5A molecular sieve. Recently, experiments including tritium were conducted using practical-scale adsorbers. These tests used existing cryogenic molecular sieve beds (CMSB's) which each contain about 1.6 kg of Linde 5A molecular sieve. They are part of the TSTA integrated tritium processing system. Gas was fed to each CMSB at about 13 SLPM with a nominal composition of 99% He, 0.98% H 2 and 0.02% HT. In all cases, for an extended period of time, the beds allowed no detectable (via Raman spectroscopy) hydrogen isotopes to escape in the bed effluent. Thereafter, the hydrogen isotopes appeared in the bed exit with a relatively sharp breakthrough curve. This work concludes that cryogenic molecular sieve adsorption is an practical and effective means of separating low-concentration hydrogen isotopes from a helium carrier

  9. A solution for the helium problem. Cryogen-free cooling systems for low temperatures; Eine Loesung fuer das Heliumproblem. Kryogenfreie Kuehlsysteme fuer tiefe Temperaturen

    Energy Technology Data Exchange (ETDEWEB)

    Good, Jeremy [Cryogenic Limited, London (United Kingdom)

    2014-09-15

    Pulse tube or Gifford-McMahon coolers are related to Stirling engines. Extremely low temperatures - 1 K can be reached with these devices. As a cryogen-free system the devices need only small amounts of helium as working gas. This fact reduces the gaseous and liquid helium consumption of research labs considerably and allows new applications. The cost-efficiency of this alternative technique is important for research facilities that use superconducting magnets.

  10. Heat transfer in cryogenic helium gas by turbulent Rayleigh-Bénard convection in a cylindrical cell of aspect ratio 1

    Czech Academy of Sciences Publication Activity Database

    Urban, Pavel; Hanzelka, Pavel; Musilová, Věra; Králík, Tomáš; La Mantia, M.; Srnka, Aleš; Skrbek, L.

    2014-01-01

    Roč. 16, č. 5 (2014), 053042: 1-40 ISSN 1367-2630 R&D Projects: GA ČR GPP203/12/P897 Institutional support: RVO:68081731 Keywords : Rayleigh-Bénard convection * heat transfer efficiency * cryogenic helium Subject RIV: BK - Fluid Dynamics Impact factor: 3.558, year: 2014

  11. Measured Performance of Four New 18 kW@4.5 K Helium Refrigerators for the LHC Cryogenic System

    CERN Document Server

    Gruehagen, Henning

    2005-01-01

    The cryogenic system for the Large Hadron Collider (LHC) under construction at CERN will include four new 4.5 K-helium refrigerators, to cover part of the cooling needs of the LHC at the 4.5-20 K and 50-75 K levels. Two refrigerators are delivered by Air Liquide, France, and two by Linde Kryotechnik, Switzerland. During the last three years, all four refrigerators have been installed and commissioned at four different points along the LHC. The specified requirements of the refrigerators are presented, with special focus on the capacities at the various temperature levels. The capacities of the refrigerators were measured using a dedicated test cryostat, and the measured performance for all four installations is presented, and compared to the guaranteed performance in the original proposal of the suppliers. Finally, the process design of the two supplies is compared, and their differences and similarities briefly analysed.

  12. Premiers résultats en provenance du LEP2

    CERN Multimedia

    CERN Press Office. Geneva

    1996-01-01

    CERN's Large Electron-Positron collider, LEP, produced its first pair of fundamental particles known as W+ and W- today, taking particle physics research into new and unexplored territory. This follows a busy winter of upgrades which have transformed LEP into a new accelerator, earning it the name LEP2. Hundreds of physicists from all over the world come to CERN to do their research at LEP2, which will be further upgraded over the coming years, bringing the possibility of new discoveries and extending our understanding of the Universe.

  13. Report of the 1997 LEP2 working group on 'searches'

    International Nuclear Information System (INIS)

    Allanach, B.C.; Blair, G.A.; Diaz, M.A.

    1997-08-01

    A number of research program reports are presented from the LEP2 positron-electron collider in the area of searches for Higgs bosons, supersymmetry and supergravity. Working groups' reports cover prospective sensitivity of Higgs boson searches, radiative corrections to chargino production, charge and colour breaking minima in minimal Supersymmetric Standard Model, R-party violation effects upon unification predictions, searches for new pair-produced particles, single sneutrino production and searches related to effects similar to HERA experiments. The final section of the report summarizes the LEP 2 searches, concentrating on gians from running at 200 GeV and alternative paradigms for supersymmetric phenomenology. (UK)

  14. Beating liquid helium: the technologies of cryogen-free superconducting magnets

    Science.gov (United States)

    Burgoyne, John

    2015-03-01

    Cryogen-free superconducting magnets have been available now for almost 15 years, but have only become standard commercial products in more recent years. In this review we will consider the pros and cons of ``dry'' design including superconducting wire development and selection, thermal budgeting, and the alternative methods for achieving magnet cooling.

  15. The use of cryogenic helium for classical turbulence: Promises and hurdles

    International Nuclear Information System (INIS)

    Niemela, J.J.; Sreenivasan, K.R.

    2006-12-01

    Fluid turbulence is a paradigm for non-linear systems with many degrees of freedom and important in numerous applications. Because the analytical understanding of the equations of motion is poor, experiments and, lately, direct numerical simulations of the equations of motion, have been fundamental to making progress. In this vein, a concerted experimental effort has been made to take advantage of the unique properties of liquid and gaseous helium at low temperatures near or below the critical point. We discuss the promise and impact of results from recent helium experiments and identify the current technical barriers which can perhaps be removed by low temperature researchers. We focus mainly on classical flows that utilize helium above the lambda line, but touch on those aspects below that exhibit quasi-classical behavior. (author)

  16. Heat flux to the helium cryogenic system elements in the case of incidental vacuum vessel ventilation with atmospheric air

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    The selection process for size in safety equipment for cold vessels or process pipes in cryogenic systems should take into consideration the incidental ventilation of the vacuum vessel with atmospheric air. In this case, a significant heat input toward the cold elements of the system can be expected. A number of experimental investigations have been done for the elements at liquid helium temperature which have been covered with 10 layers of MLI. The typical values of the heat flux were measured in a range of 3.7 to 5.0 kW/m2 of the element surface. The helium temperature parts are typically surrounded by thermal shields that are kept in a temperature range of 50-80K. On the external side, the thermal shields are covered with 30-40 layers of MLI while on the internal side, the shields are bare. The theoretical calculations of heat flux to the thermal shield, with respect to the possibility of air condensation and freezing on the bare side of the thermal shield, show that the heat flux to the thermal shield can...

  17. Fermion pair production at LEP2 and interpretations

    International Nuclear Information System (INIS)

    Abbiendi, G.

    2001-01-01

    Preliminary results on e + e - → f f-bar, f = e, μ, τ, q, including all LEP2 data are discussed. Good agreement is found with the Standard Model up to the highest energies. Limits on possible new physics are extracted

  18. Modelling Bose-Einstein correlations at LEP-2

    International Nuclear Information System (INIS)

    Loennblad, L.

    1998-01-01

    Some pros and cons of different strategies for modelling Bose-Einstein correlations in event generators for fully hadronic WW events at LEP-2 are discussed. A few new algorithms based on shifting final-state momenta of identical bosons in WW events generated by PYTHIA are also presented and the resulting predictions for the effects on the W mass measurement are discussed. (author)

  19. Experimental study on cryogenic adsorption of methane by activated carbon for helium coolant purification of High-Temperature Gas-cooled Reactor

    International Nuclear Information System (INIS)

    Chang, Hua; Wu, Zong-Xin; Jia, Hai-Jun

    2017-01-01

    Highlights: • The cryogenic CH 4 adsorption on activated carbon was studied for design of HTGR. • The breakthrough curves at different conditions were analyzed by the MTZ model. • The CH 4 adsorption isotherm was fitted well by the Toth model and the D-R model. • The work provides valuable reference data for helium coolant purification of HTGR. - Abstract: The cryogenic adsorption behavior of methane on activated carbon was investigated for helium coolant purification of high-temperature gas-cooled reactor by using dynamic column breakthrough method. With helium as carrier gas, experiments were performed at −196 °C and low methane partial pressure range of 0–120 Pa. The breakthrough curves at different superficial velocities and different feed concentrations were measured and analyzed by the mass-transfer zone model. The methane single-component adsorption isotherm was obtained and fitted well by the Toth model and the Dubinin-Radushkevich model. The adsorption heat of methane on activated carbon was estimated. The cryogenic adsorption process of methane on activated carbon has been verified to be effective for helium coolant purification of high-temperature gas-cooled reactor.

  20. Cryogenics

    International Nuclear Information System (INIS)

    Gutierrez R, C.; Jimenez D, J.; Cejudo A, J.; Hernandez M, V.

    1997-01-01

    Cryogenics is one of these technologies which contributes to scientific research that supports to the industry in the following benefits: 1. Storage ability and a great quantity of dense gases with cryogenic liquid which is found at high pressure. 2. Production ability at low cost with high purity gases through distillation or condensation. 3. Ability to use low temperatures in the refrigerating materials or alteration of the physical properties. This technology is used for reprocessing of those short and long half life radioactive wastes which always have been required that to be separated with classical methods. In this text we report the radioactive wastes separation by more sophisticated methods but more quickly and reliable. (Author)

  1. Helium leak testing of superconducting magnets, thermal shields and cryogenic lines of SST -1

    International Nuclear Information System (INIS)

    Thankey, P.L.; Joshi, K.S.; Semwal, P.; Pathan, F.S.; Raval, D.C.; Khan, Z.; Patel, R.J.; Pathak, H.A.

    2005-01-01

    Tokamak SST - 1 is under commissioning at Institute for Plasma Research. It comprises of a toroidal doughnut shaped plasma chamber, surrounded by liquid helium cooled superconducting magnets, housed in a cryostat chamber. The cryostat has two cooling circuits, (1) liquid nitrogen cooling circuit operating at 80 K to minimize the radiation heat load on the magnets, and (2) liquid helium cooling circuit to cool magnets and cold mass support structure to 4.5 K. In this paper we describe (a) the leak testing of copper - SS joints, brazing joints, interconnecting joints of the superconducting magnets, and (b) the leak testing of the liquid nitrogen cooling circuit, comprising of the main supply header, the thermal shields, interconnecting pipes, main return header and electrical isolators. All these tests were carried out using both vacuum and sniffer methods. (author)

  2. Proposal to negotiate, without competitive tendering, a contract for the manufacture, testing and delivery of 320 cryogenic helium mass flowmeters for the LHC

    CERN Document Server

    2001-01-01

    This document concerns the manufacture, testing and delivery of 320 cryogenic helium mass flowmeters for the LHC. Following a market survey (MS-2602/LHC/LHC) carried out amoung 37 firms in twelve Member States and six firms in two non-Member States, a price enquiry for qualifying prototypes was sent on 20 November 1998 to nine selected firms and the received prototypes were evaluated. As a result of this process a request for quotation was sent to one firm The Finance Committee is invited to agree to the negotiation of a contract with the firm EMERSON PROCESS MANAGEMENT/FISHER-ROSEMOUNT (CH), without competitive tendering, for the manufacture, testing and delivery of 320 cryogenic helium mass flowmeters for an amount of 1 804 840 Swiss francs, not subject to revision, with options for up to 10 additional cryogenic helium mass flowmeters and an extension of the guarantee period to five years for all units for an amount of 219 090 Swiss francs, not subject to revision, bringing the total amount to 2 023 930 Swi...

  3. Proposal for the award of an industrial services contract for the operation and maintenance of liquid helium cryogenic plants

    CERN Document Server

    2000-01-01

    This document concerns the award of an Industrial Services contract for the operation and maintenance of liquid helium cryogenic plants. Following a market survey carried out among 54 firms in twelve Member States, a call for tenders (IT-2719/LHC) was sent on 18 August 2000 to two firms and four consortia, two consisting of two firms and two consisting of three firms, in five Member States. By the closing date, CERN had received tenders from one firm and three consortia, in four Member States. The Finance Committee is invited to agree to the negotiation of a contract with the consortium AIR LIQUIDE (FR) - LINDE KRYOTECHNIK (CH) - SERCO (DE), the lowest bidder, for an initial period of four years from 17 July 2001 for a total amount of 19 804 400 Swiss francs, not subject to revision until 16 July 2005. The contract will include options for two one-year extensions beyond the initial four-year period. The consortium has indicated the following distribution by country of the contract value covered by this adjudi...

  4. Hard photons in W pair production at LEP 2

    International Nuclear Information System (INIS)

    Oldenborgh, G.J. van

    1996-01-01

    The properties of hard photon radiation in W pair production at LEP 2 are studied, with emphasis on the energy loss relevant to the W mass measurement. We use a combination of the exact one-photon matrix element and leading logarithmic structure functions. Defining unobservable, observable and initial-state photons in the phase space, it is shown that neither the one-photon matrix element nor the leading logarithmic structure functions alone give an adequate description of the energy loss due to observable or initial-state photons. An event generator based on these calculations is available. (orig.)

  5. Radiative four-fermion processes at LEP2

    International Nuclear Information System (INIS)

    Montagna, G.; Nicrosini, O.; Osmo, M.; Piccinini, F.; Moretti, M.

    2001-01-01

    The production of four fermions plus a visible photon in electron-positron collisions is analyzed, with particular emphasis on the LEP2 energy range. The study is based on the calculation of exact matrix elements, including the effect of fermion masses. In the light of the present measurements performed at LEP, triple and quartic anomalous gauge couplings are taken into account. Due to the presence of a visible photon in the final state, particular attention is paid to the treatment of higher-order QED corrections. Explicit results for integrated cross sections and differential distributions are shown and commented on. The features of the Monte Carlo program WRAP, used to perform the calculation and available for experimental analysis, are described. (orig.)

  6. Proposal for the award of a contract for the supply and installation of the cryogenic helium refrigeration system for the CMS experiment

    CERN Document Server

    1999-01-01

    This document concerns the award of a contract for the supply and installation of the cryogenic helium refrigeration system for the CMS Experiment. Following a market survey carried out among 22 firms in seven Member States and seven firms in two non-Member States, a call for tenders (IT-2576/EP/CMS) was sent on 17 February 1999 to two firms in two Member States and one firm in one non-Member State. By the closing date, CERN had received two tenders. The Finance Committee is invited to agree to the negotiation of a contract with AIR LIQUIDE (FR), the lowest bidder, for the supply and installation of a cryogenic helium refrigeration system for an amount of 4 552 500 euros, subject to revision, with an option for one liquid nitrogen dewar and a one-year extension of the warranty period, for an amount of 205 000 euros, subject to revision, bringing the total amount to 4 757 500 euros. At the rate of exchange given in the tender, this amount is equal to 7 612 000 Swiss francs. This procurement will be financed by...

  7. New development of hadron physics at new laser electron beam line (LEP2) of SPring-8

    International Nuclear Information System (INIS)

    Muramatsu, Norihito; Niiyama, Masayuki; Yosoi, Masaru

    2015-01-01

    This paper introduces the outline of LEPS2 beam line and two types of large detectors (electromagnetic calorimeter BGOegg and solenoid spectrometer), LEPS2/BGOegg experiment, and the target physics using LEPS2 solenoid spectrometer. In LEPS2 beam line, experiments are performed with the improvement of beam intensity by nearly one digit due to the simultaneous incidence of multiple lasers of high output, as well as with the installation of a large solid angle high-resolution detector. In LEPS2/BGOegg experiment, direct observation with a large solid angle of mesons such as π 0 , η, η', and ω has become possible, which has given expectation for new physics. As one of the physics at the core of BGOegg experiments, there is the systematic examination of interaction between η' and nucleus/nucleon. In the physics using a solenoid spectrometer, the first target is the measurement of penta-quark particle Θ + . (A.O.)

  8. Liquid helium target

    International Nuclear Information System (INIS)

    Fujii, Y.; Kitami, T.; Torikoshi, M.

    1984-12-01

    A liquid helium target system has been built and used for the experiment on the reaction 4 He(γ, p). The target system has worked satisfactorily; the consumption rate of liquid helium is 360 ml/h and the cryogenic system retains liquid helium for about ten hours. The structure, operation and performance of the target system are reported. (author)

  9. Tritium recovery from helium purge stream of solid breeder blanket by cryogenic molecular sieve bed. 2. Regeneration operation of cryogenic molecular sieve bed

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, Yoshinori; Enoeda, Mikio; Nishi, Masataka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Regeneration operation is a very important operation, because it is the most influential factor for deciding the net operation cycle time and the minimum dimension of Cryogenic Molecular Sieve Bed (CMSB). However, the experimental data of CMSB regeneration operation was not so sufficient that even the optimum regeneration procedure could not be decided yet. This work was focused on getting the primary information about various regeneration procedures. (author)

  10. Large strip RPCs for the LEPS2 TOF system

    Energy Technology Data Exchange (ETDEWEB)

    Tomida, N., E-mail: natsuki@scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Niiyama, M. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Ohnishi, H. [RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198 (Japan); Tran, N. [Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Hsieh, C.-Y.; Chu, M.-L.; Chang, W.-C. [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Chen, J.-Y. [National Synchrotron Radiation Research Center (NSRRC), Hsinchu 30076, Taiwan (China)

    2014-12-01

    High time-resolution resistive plate chambers (RPCs) with large-size readout strips are developed for the time-of-flight (TOF) detector system of the LEPS2 experiment at SPring-8. The experimental requirement is a 50-ps time resolution for a strip size larger than 100 cm{sup 2}/channel. We are able to achieve 50-ps time resolutions with 2.5×100 cm{sup 2} strips by directly connecting the amplifiers to strips. With the same time resolution, the number of front-end electronics (FEE) is also reduced by signal addition. - Highlights: • Find a way to achieve a good time resolution with a large strip RPC. • 2.5 cm narrow strips have better resolutions than 5.0 cm ones. • The 0.5 mm narrow strip interval shows flat time resolutions between strips. • FEEs directly connected to strips make the signal reflection at the strip edge small. • A time resolution of 50 ps was achieved with 2.5 cm×100 cm strips.

  11. Measurement and control system for cryogenic helium gas bearing turbo-expander experimental platform based on Siemens PLC S7-300

    Science.gov (United States)

    Li, J.; Xiong, L. Y.; Peng, N.; Dong, B.; Wang, P.; Liu, L. Q.

    2014-01-01

    An experimental platform for cryogenic Helium gas bearing turbo-expanders is established at the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences. This turbo-expander experimental platform is designed for performance testing and experimental research on Helium turbo-expanders with different sizes from the liquid hydrogen temperature to the room temperature region. A measurement and control system based on Siemens PLC S7-300 for this turbo-expander experimental platform is developed. Proper sensors are selected to measure such parameters as temperature, pressure, rotation speed and air flow rate. All the collected data to be processed are transformed and transmitted to S7-300 CPU. Siemens S7-300 series PLC CPU315-2PN/DP is as master station and two sets of ET200M DP remote expand I/O is as slave station. Profibus-DP field communication is established between master station and slave stations. The upper computer Human Machine Interface (HMI) is compiled using Siemens configuration software WinCC V6.2. The upper computer communicates with PLC by means of industrial Ethernet. Centralized monitoring and distributed control is achieved. Experimental results show that this measurement and control system has fulfilled the test requirement for the turbo-expander experimental platform.

  12. Measurement and control system for cryogenic helium gas bearing turbo-expander experimental platform based on Siemens PLC S7-300

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.; Xiong, L. Y.; Peng, N.; Dong, B.; Liu, L. Q. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China); Wang, P. [Beijing Sciample Technology Co., Ltd., Beijing, 100190 (China)

    2014-01-29

    An experimental platform for cryogenic Helium gas bearing turbo-expanders is established at the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences. This turbo-expander experimental platform is designed for performance testing and experimental research on Helium turbo-expanders with different sizes from the liquid hydrogen temperature to the room temperature region. A measurement and control system based on Siemens PLC S7-300 for this turbo-expander experimental platform is developed. Proper sensors are selected to measure such parameters as temperature, pressure, rotation speed and air flow rate. All the collected data to be processed are transformed and transmitted to S7-300 CPU. Siemens S7-300 series PLC CPU315-2PN/DP is as master station and two sets of ET200M DP remote expand I/O is as slave station. Profibus-DP field communication is established between master station and slave stations. The upper computer Human Machine Interface (HMI) is compiled using Siemens configuration software WinCC V6.2. The upper computer communicates with PLC by means of industrial Ethernet. Centralized monitoring and distributed control is achieved. Experimental results show that this measurement and control system has fulfilled the test requirement for the turbo-expander experimental platform.

  13. Bose-Einstein correlations in DELPHI WW events at LEP2

    International Nuclear Information System (INIS)

    Abreua, P.

    2006-01-01

    The preliminary results on the study of Bose-Einstein Correlations between particles coming from different W bosons, in DELPHI WW events at LEP2, are presented. This manuscript is dedicated to the memory of Frans Verbeure

  14. MOSFET's for Cryogenic Amplifiers

    Science.gov (United States)

    Dehaye, R.; Ventrice, C. A.

    1987-01-01

    Study seeks ways to build transistors that function effectively at liquid-helium temperatures. Report discusses physics of metaloxide/semiconductor field-effect transistors (MOSFET's) and performances of these devices at cryogenic temperatures. MOSFET's useful in highly sensitive cryogenic preamplifiers for infrared astronomy.

  15. Steady state heat transfer experimental studies of LHC superconducting cables operating in cryogenic environment of superfluid helium

    CERN Document Server

    Santandrea, Dario; Tuccillo, Raffaele; Granieri, Pier Paolo

    The heat management is a basic and fundamental aspect of the superconducting magnets used in the CERN Large Hadron Collider. Indeed, the coil temperature must be kept below the critical value, despite the heat which can be generated or deposited in the magnet during the normal operations. Therefore, this thesis work aims at determining the heating power which can be extracted from the superconducting cables of the LHC, specially through their electrical insulation which represents the main thermal barrier. An experimental measurement campaign in superfluid helium bath was performed on several samples reproducting the main LHC magnets. The heating power was generated in the sample by Joule heating and the temperature increase was measured by means of Cernox bare chip and thermocouples. An innovative instrumentation technique which also includes the in-situ calibration of the thermocouples was developed. A thorough uncertainty analysis on the overall measurement chain concluded the experimental setup. The prese...

  16. Cooling with Superfluid Helium

    Energy Technology Data Exchange (ETDEWEB)

    Lebrun, P; Tavian, L [European Organization for Nuclear Research, Geneva (Switzerland)

    2014-07-01

    The technical properties of helium II (‘superfluid’ helium) are presented in view of its applications to the cooling of superconducting devices, particularly in particle accelerators. Cooling schemes are discussed in terms of heat transfer performance and limitations. Large-capacity refrigeration techniques below 2 K are reviewed, with regard to thermodynamic cycles as well as process machinery. Examples drawn from existing or planned projects illustrate the presentation. Keywords: superfluid helium, cryogenics.

  17. Two-photon collisions at very low Q2 from LEP2. Forthcoming results

    International Nuclear Information System (INIS)

    Almehed, S.; Jarlskog, G.; Mjornmark, U.; Nygren, A.; Zimin, N.; Kapusta, F.; Tyapkin, I.

    1998-01-01

    Experimental results that may soon be obtained in two-photon collisions at very low momentum transfer Q 2 at LEP2 are reviewed. A kinematical range is presented for both the forward and very forward detectors used to measure scattered electrons and positrons. A new acceptance, after this year's upgrade of the beam pipe at the position of the very forward detectors, is evaluated. The corresponding statistics is calculated for an integrated luminosity of 400 pb -1 , that must be collected by the end of LEP2 operation according to current plans

  18. Cool Down Experiences with the SST-1 Helium Cryogenics System before and after Current Feeders System Modification

    Science.gov (United States)

    Patel, R.; Panchal, P.; Panchal, R.; Tank, J.; Mahesuriya, G.; Sonara, D.; Srikanth, G. L. N.; Garg, A.; Bairagi, N.; Christian, D.; Patel, K.; Shah, P.; Nimavat, H.; Sharma, R.; Patel, J. C.; Gupta, N. C.; Prasad, U.; Sharma, A. N.; Tanna, V. L.; Pradhan, S.

    The SST-1 machine comprises a superconducting magnet system (SCMS), which includes TF and PF magnets. In order to charge the SCMS, we need superconducting current feeders consisting of SC feeders and vapor cooled current leads (VCCLs). We have installed all 10 (+/-) pairs of VCCLs for the TF and PF systems. While conducting initial engineering validation of the SST-1 machine, our prime objective was to produce circular plasma using only the TF system. During the SST-1 campaign I to VI, we have to stop the PF magnets cooling in order to get the cryo- stable conditions for current charging of the TF magnets system. In that case, the cooling of the PF current leads is not essential. It has been also observed that after aborting the PF system cooling, there was a limited experimental window of TF operation. Therefore, in the recent SST-1 campaign-VII, we removed the PF current leads (9 pairs) and kept only single (+/-) pair of the 10,000 A rated VCCLs to realize the charging of the TF system for the extended window of operation. We have observed a better cryogenic stability in the TF magnets after modifications in the CFS. In this paper, we report the comparison of the cool down performance for the SST-1 machine operation before and after modifications of the current feeders system.

  19. Search for charged Higgs bosons at LEP2 with Delphi detector; Recherche des bosons de higgs charges a LEP2 avec le detecteur DELPHI

    Energy Technology Data Exchange (ETDEWEB)

    Silvestre, R

    1997-09-01

    Charged Higgs bosons are particles that are predicted by most theoretical models based on the minimal standard model, they are responsible for the breaking of the symmetry implied by the gauge group SU(2){sub L}*U(1){sub Y}. This work is devoted to the search after this particle in the experimental data collected by the DELPHI experiment. Different analysis strategies have been defined to study the 3 possible final states: H{sup +}H{sup -} {yields} {tau}{sup +}{nu}{sub {tau}}{tau}{sup -}{nu}-bar{sub {tau}}, H{sup +}H{sup -} {yields} cs{tau}{nu}{sub {tau}} and H{sup +}H{sup -} {yields} cs-bar c-bar s. Different hypothesis have been made about the value of the branching ratio of the hadronic decay of Higgs boson. After having analysed the experimental data collected when electron-positron collision energy was 161.3 GeV (in the mass center frame) the author concludes that: m{sub H} > 48.7 GeV/c{sup 2} if Br(H{sup +} {yields} hadrons) < 0.6 (90% CL). A similar analysis performed on all the experimental data leads to: m{sub H} > 52 GeV/c{sup 2} if Br(H{sup +} {yields} hadrons) < 0.7 (95% CL). At the end of 1995 the LEP collider entered a new operating phase (LEP2) which would eventually enable the collision energy to reach 192 GeV in the mass center frame. An analysis of a simulation representing LEP2 operating at 192 GeV has been made. From this analysis the author concludes first that it will be possible to discover a Higgs boson in LEP2 only if its mass is less than 60 GeV/c{sup 2}, secondly that if no Higgs boson is detected at the end of LEP2 phase, it will mean that its mass is greater than 70 GeV/c{sup 2}. (A.C.)

  20. CEBAF cryogenic system

    International Nuclear Information System (INIS)

    Brindza, P.; Rode, C.

    1986-01-01

    The Continuous Electron Beam Accelerator Facility (CEBAF) is a standing wave superconducting linear accelerator with a maximum energy of 4 GeV and 200 μA beam current. The 418 Cornell/CEBAF superconducting niobium accelerating cavities are arranged in two 0.5 GeV linacs with magnetic recirculating arcs at each end. These accelerating cavities are arranged in pairs in a cryounit. The ensemble of four cryounits (8 cavities) together with their end caps makes up a complete cryostat called a cryogenic module. The four cryounit helium vessels are cross connected to each other and share a common cryogen supply, radiation shield and insulating vacuum. The cryogenics system for CEBAF consists of a 5kW central helium refrigerator and a transfer line system to supply 2.2 K 2.8 ATM helium to the cavity cryostats, 40 K helium at 3.5 ATM to the radiation shields and 4.5K helium at 2.8 ATM to the superconducting magnetic spectrometers in the experimental halls. Both the 2.2 K and the 4.5 K helium are expanded by Joule-Thompson (JT) valves in the individual cryostats yielding 2.0 K at .031 ATM and 4.4 K at 1.2 ATM respectively. The Central Helium Refrigerator is located in the center of the CEBAF racetrack with the transfer lines located in the linac tunnels

  1. CP-violating MSSM Higgs bosons in the light of LEP 2

    International Nuclear Information System (INIS)

    Carena, M.; Ellis, J.; Pilaftsis, A.; Wagner, C.E.M.

    2000-01-01

    In the MSSM, the CP parities of the neutral Higgs bosons may be mixed by radiative effects induced by explicit CP violation in the third generation of squarks. To allow for this possibility, we argue that the charged Higgs-boson mass and tanβ should be used to parametrize the MSSM Higgs sector. We introduce a new benchmark scenario of maximal CP violation appropriate for direct searches of CP-violating MSSM Higgs bosons. We show that the bounds established by LEP 2 on the MSSM Higgs sector may be substantially relaxed at low and intermediate values of tanβ in the presence of CP violation, and comment on possible Higgs boson signatures at LEP 2 within this framework.

  2. Operating Manual of Helium Refrigerator (Rev. 2)

    Energy Technology Data Exchange (ETDEWEB)

    Song, K.M.; Son, S.H.; Kim, K.S.; Lee, S.K.; Kim, M.S. [Korea Electric Power Research Institute, Taejon (Korea)

    2002-07-01

    A helium refrigerator was installed as a supplier of 20K cold helium to the cryogenic distillation system of WTRF pilot plant. The operating procedures of the helium refrigerator, helium compressor and auxiliary apparatus are described for the safety and efficient operation in this manual. The function of the helium refrigerator is to remove the impurities from the compressed helium of about 250psig, to cool down the helium from ambient temperature to 20K through the heat exchanger and expansion engine and to transfer the cold helium to the cryogenic distillation system. For the smoothly operation of helium refrigerator, the preparation, the start-up, the cool-down and the shut-down of the helium refrigerator are described in this operating manual. (author). 3 refs., 14 tabs.

  3. Cryogenic system for TRISTAN superconducting RF cavity

    International Nuclear Information System (INIS)

    Hosoyama, K.; Hara, K.; Kabe, A.; Kojima, Yuuji; Ogitsu, T.; Sakamoto, Y.; Kawamura, S.; Ishimaru, Y.

    1990-01-01

    A cryogenic system consisting of a helium refrigerator (4 kW at 4.4 K) and a liquid helium distribution transfer system for TRISTAN 508 MHz 32 x 5-cell superconducting RF cavities was designed and constructed. After the performance test of the cryogenic system, 16 x 5-cell superconducting RF cavities in 8 cryostats were installed in underground TRISTAN electron-positron collider and connected to the helium refrigerator on the ground level through the transfer line (total length about 330 m) and cooled by liquid helium pool boiling in parallel. The cryogenic system and its operation experience are described. (author)

  4. Cryogenics will cool LHC

    International Nuclear Information System (INIS)

    Anon.

    2001-01-01

    Results of the investigation into the cryogenic regulating line (QRL) performed by the LHC laboratory are presented. It is projected that eight cryogenic units located in five places around the LHC ring will provide superconducting magnets by liquid helium through eight cryogenic regulating lines of 3.2 km each. All QRL zones remain to be independent. CERN uses three test units with the aim of the certification of chosen constructions and verification of their thermal and mechanical efficiency before starting full-scale production [ru

  5. TPC magnet cryogenic system

    International Nuclear Information System (INIS)

    Green, M.A.; Burns, W.A.; Taylor, J.D.; Van Slyke, H.W.

    1980-03-01

    The Time Projection Chamber (TPC) magnet at LBL and its compensation solenoids are adiabatically stable superconducting solenoid magnets. The cryogenic system developed for the TPC magnet is discussed. This system uses forced two-phase tubular cooling with the two cryogens in the system. The liquid helium and liquid nitrogen are delivered through the cooled load by forced tubular flow. The only reservoirs of liquid cryogen exist in the control dewar (for liquid helium) and the conditioner dewar (for liquid nitrogen). The operation o these systems during virtually all phases of system operation are described. Photographs and diagrams of various system components are shown, and cryogenic system data are presented in the following sections: (1) heat leaks into the TPC coil package and the compensation solenoids; (2) heat leaks to various components of the TPC magnet cryogenics system besides the magnets and control dewar; (3) the control dewar and its relationship to the rest of the system; (4) the conditioner system and its role in cooling down the TPC magnet; (5) gas-cooled electrical leads and charging losses; and (6) a summation of the liquid helium and liquid nitrogen requirements for the TPC superconducting magnet system

  6. CERN LEP2 constraint on 4D QED having a dynamically generated spatial dimension

    International Nuclear Information System (INIS)

    Cho, G.-C.; Izumi, Etsuko; Sugamoto, Akio

    2002-01-01

    We study 4D QED in which one spatial dimension is dynamically generated from the 3D action, following the mechanism proposed by Arkani-Hamed, Cohen, and Georgi. In this model, the generated fourth dimension is discretized by an interval parameter a. We examine the phenomenological constraint on the parameter a coming from collider experiments on the QED process e + e - →γγ. It is found that the CERN e + e - collider LEP2 experiments give the constraint of 1/a > or approx. 461 GeV. The expected bound on the same parameter a at a future e + e - linear collider is briefly discussed

  7. Search for extra spatial dimensions and TeV scale quantum gravity at LEP-2

    International Nuclear Information System (INIS)

    Litke, A.M.

    2001-01-01

    A number of measurements which probe the experimental consequences of extra spatial dimensions and TeV scale quantum gravity are accessible at the LEP-2 electron-positron collider. Preliminary results on the following processes, performed with the ALEPH detector at center of mass energies around 200 GeV, are presented: 1. search for direct graviton production in the reaction e + e - →γG; and, 2. search for effects due to virtual graviton exchange in the reactions e + e - →γγ and fermion-anti-fermion pairs

  8. Bose-Einstein correlations in W+ W- events at LEP2

    CERN Document Server

    van Dalen, Jorn A

    2000-01-01

    Analyses of Bose-Einstein Correlations in w+w- events at LEP2 by the four LEP collaborations are presented. In particular, Bose-Einstein correlations in w+w- overlap are investigated and the possible existence of these correlations between particles coming from different W's, which may influence the W mass measurements in the fully-hadronic channel e+e- --+ w+w- --+ qiihq3ij<. No evidence for such an inter-W Bose-Einstein correlation is found by L3 and ALEPH. Possible indication of these correlations by DELPHI is mentioned.

  9. Heavy quark and quarkonium production at CERN LEP2. kT-factorization versus data

    International Nuclear Information System (INIS)

    Lipatov, A.V.; Zotov, N.P.

    2005-02-01

    We present calculations of heavy quark and quarkonium production at CERN LEP2 in the κ T -factorization QCD approach. Both direct and resolved photon contribution are taken into account. The conservative error analysis is performed. The unintegrated gluon distribution in the photon is obtained from the full CCFM evolution equation. The traditional color-singlet mechanism to describe non-perturbative transition of QQ-pair into a final quarkonium is used. Our analysis covers polarization properties of heavy quarkonia at moderate and large transverse momenta. We find that the total and differential open charm production cross sections are consistent with the recent experimental data taken by the L3, OPAL and ALEPH collaborations. At the same time the DELPHI data for the inclusive J/ψ production exceed our predictions but experimental uncertainties are too large to claim a significant inconsistency. The bottom production in photon-photon collisions at CERN LEP2 is hard to explain within the κ T -factorization formalism. (orig.)

  10. Reports of the working groups on precision calculations for LEP2 physics. Proceedings

    International Nuclear Information System (INIS)

    Jadach, S.; Passarino, G.; Pittau, R.

    2000-01-01

    This is the report of the LEP2 Monte Carlo Workshop held at CERN from 1999 to 2000. It consists of four parts. In the first part, the most recent developments in the calculation of four-fermion processes in electron-positron collisions at LEP2 are presented, concentrating on predictions for four main reactions: W-pair production, visible photons in four-fermion events, single-W production, and Z-pair production. Based on a comparison of results within different approaches, theoretical uncertainties on these prediction are established. The second part is devoted to QCD issues, focusing on improving the understanding and the Monte Carlo simulation of multijet final states due to hard QCD processes at LEP, i.e. quark-antiquark plus multigluon and/or secondary quark production, with particular emphasis on four-jet final states and b-quark mass effects. Specific topics covered are: relevant developments in the main event generators; description and tuning of inclusive (all-flavour) jet rates; quark mass effects in the three- and four-jet rates; mass, higher-order and hadronization effects in four-jet angular and shape distributions; b-quark fragmentation and gluon splitting into b-quarks. In the third part, γγ physics is discussed. After a detailed description of the physics modelling of the most recent versions of the currently available codes, comparisons between the results of the different event generators, as well as between LEP data and the theoretical predictions are presented, together with the problem of background due to γγ processes in searches for new particles. In the last part, recent developments in the theoretical calculation of two-fermion processes are reported. The Bhabha process and the production of muon, tau, neutrino and quark pairs is covered. On the basis of comparison of various calculations, theoretical uncertainties are estimated and compared with those needed for the final LEP2 data analysis. The subjects for further study are identified

  11. Search for Supersymmetric Particles with the OPAL Detector at LEP2

    CERN Document Server

    Kanaya, N

    A search of Supersymmetric particles was performed using the data collected in 1999 and 2000 by the Opal detector at the LEP2 e+e- collider. The center-of-mass energies ranged from 192 GeV to 209 GeV, and the data analyzed correspond to an integrated luminosity of 432 pb-1. Supersymmetric models permit a large number of different experimental final states which should all be investigated. The search presented here is sensitive to final states with photons plus additional detector activity with missing energy. these topologies are characteristic of events expected in Gauge-Mediated Supersymmetry Breaking (GMSB) models. No significant evidence for their existence is observed. Finally, using various search results at centre-of-mass energy of 189 GeV, constraints on the parameters have been given within the framework of the minimal GMSB model.

  12. Search for γ-Z-Z' electroweak interference at e+e- collider LEP2

    International Nuclear Information System (INIS)

    Pankov, A.A.

    2000-01-01

    Indirect effects of Z' bosons at the e + e - collider LEP2 in e + e - → μ + μ - through the new integrated observables σ ± were studied. It is shown that these observables provide more definite information on Z' effects with respect to canonical observables, σ μμ and A FB . It is found that the deviations Δσ ± induced by Z' bosons have the specific energy dependence mostly defined by the Standard Model parameters. It allows to provide the unambiguous model-independent predictions for the deviations. In particular, there were found two energies, √s + ≅ 78 GeV and √s - = 113 GeV, where σ + and σ - vanish both in the Standard Model and in case of Z'. These energies are quite convenient to search for phenomenological consequences of alternative new physics sources beyond the Z' [ru

  13. Heat switch technology for cryogenic thermal management

    Science.gov (United States)

    Shu, Q. S.; Demko, J. A.; E Fesmire, J.

    2017-12-01

    Systematic review is given of development of novel heat switches at cryogenic temperatures that alternatively provide high thermal connection or ideal thermal isolation to the cold mass. These cryogenic heat switches are widely applied in a variety of unique superconducting systems and critical space applications. The following types of heat switch devices are discussed: 1) magnetic levitation suspension, 2) shape memory alloys, 3) differential thermal expansion, 4) helium or hydrogen gap-gap, 5) superconducting, 6) piezoelectric, 7) cryogenic diode, 8) magneto-resistive, and 9) mechanical demountable connections. Advantages and limitations of different cryogenic heat switches are examined along with the outlook for future thermal management solutions in materials and cryogenic designs.

  14. Status of the Cryogenic System Commissioning at SNS

    CERN Document Server

    Casagrande, Fabio; Campisi, Isidoro E; Creel, Jonathan; Dixon, Kelly; Ganni, Venkatarao; Gurd, Pamela; Hatfield, Daniel; Howell, Matthew; Knudsen, Peter; Stout, Daniel; Strong, William

    2005-01-01

    The Spallation Neutron Source (SNS) is under construction at Oak Ridge National Laboratory. The cold section of the Linac consists of 81 superconducting radio frequency cavities cooled to 2.1K by a 2400 Watt cryogenic refrigeration system. The major cryogenic system components include warm helium compressors with associated oil removal and gas management, 4.5K cold box, 7000L liquid helium dewar, 2.1K cold box (consisting of 4 stages of cold compressors), gaseous helium storage, helium purification and gas impurity monitoring system, liquid nitrogen storage and the cryogenic distribution transfer line system. The overall system commissioning strategy and status will be presented.

  15. CEBAF cryogenic system

    International Nuclear Information System (INIS)

    1995-01-01

    The CEBAF cryogenic system consists of 3 refrigeration systems: Cryogenic Test Facility (CTF), Central Helium Liquefier (CHL), and End Station Refrigerator (ESR). CHL is the main cryogenic system for CEBAF, consisting of a 4.8 kW, 2.0 K refrigerator and transfer line system to supply 2.0 K and 12 kW of 50 K shield refrigeration for the Linac cavity cryostats and 10 g/s of liquid for the end stations. This paper describes the 9-year effort to commission these systems, concentrating on CHL with the cold compressors. The cold compressors are a cold vacuum pump with an inlet temperature of 3 K which use magnetic bearings, thereby eliminating the possibility of air leaks into the subatmospheric He

  16. Characterization of a cryogenic ion guide at IGISOL

    NARCIS (Netherlands)

    Saastamoinen, A.; Moore, I. D.; Ranjan, M.; Dendooven, P.; Penttila, H.; Perajarvi, K.; Popov, A.; Aysto, J.

    2012-01-01

    A small volume cryogenic ion guide has been characterized at the IGISOL facility, Jyvaskyla, as a prototype to verify whether there are any major obstacles to the use of high-density cryogenic helium gas for the stopping and extraction of high-energy ions from a large volume cryogenic ion catcher.

  17. Cryogenics in CEBAF HMS dipole

    International Nuclear Information System (INIS)

    Bogensberger, P.; Ramsauer, F.; Brindza, P.; Wines, R.; Koefler, H.

    1994-01-01

    The paper will report upon the final design, manufacturing and tests of CEBAF's HMS Dipole cryogenic equipment. The liquid nitrogen circuits, the helium circuits and thermal insulation of the magnet will be addressed. The cryogenic reservoir and control module as an integral part of the HMS Dipole magnet will be presented. The construction, manufacturing, tests and final performance of the HMS Dipole cryogenic system will be reported. The LN 2 circuit and the He circuit are tied together by the control system for cool down, normal operation and standby. This system monitors proper temperature differences between both circuits and controls the cryogenic supply to meet the constraints. Implementation of the control features for the cryogenic system into the control system will be reported

  18. Commissioning of cryogen delivery system for superconducting cyclotron magnet

    International Nuclear Information System (INIS)

    Pal, G.; Nandi, C.; Bhattacharyya, T.K.; Chaudhuri, J.; Bhandari, R.K.

    2005-01-01

    A K-500 superconducting cyclotron is being constructed at VECC Kolkata. The cryogen delivery system distributes liquid helium and liquid nitrogen to the superconducting cyclotron. Liquid helium is required to cool the cyclotron magnet and cryopanels. Liquid nitrogen is used to reduce the capacity of the helium liquefier. This paper describes the system, the current status and the commissioning experiences of cryogen delivery system for cyclotron magnet. (author)

  19. Little-Higgs corrections to precision data after CERN LEP2

    International Nuclear Information System (INIS)

    Marandella, Guido; Schappacher, Christian; Strumia, Alessandro

    2005-01-01

    We reconsider little-Higgs corrections to precision data. In five models with global symmetries SU(5), SU(6), SO(9) corrections are (although not explicitly) of 'universal' type. We get simple expressions for the S-circumflex,T-circumflex,W,Y parameters, which summarize all effects. In all models W,Y≥0 and in almost all models S-circumflex>(W+Y)/2. Results differ from previous analyses, which are sometimes incomplete, sometimes incorrect, and because we add LEP2 ee→ff cross sections to the data set. Depending on the model, the constraint on f ranges between 2 and 20 TeV. We next study the simplest little-Higgs model (and propose a related model) which is not universal and affects precision data due to the presence of an extra Z ' vector. By restricting the data set to the most accurate leptonic data we show how corrections to precision data generated by a generic Z ' can be encoded in four effective S-circumflex,T-circumflex,W,Y parameters, giving their expressions

  20. Distributions in four-fermion processes for W-physics at LEP 2

    International Nuclear Information System (INIS)

    Accomando, E.; Ballestrero, A.; Passarino, G.

    1996-01-01

    The programs WPHACT and WTO, which are designed for computing cross sections and other relevant observables in the e + e - annihilation into four fermions, are used to make detailed and complete predictions for the semi-leptonic and fully hadronic channels e + e - →qqlν, qqqq. Both the total cross sections in the LEP 2 energy range and some of the most relevant distributions are analyzed. Particular algorithms are introduced for the fully hadronic channels in order to analyze the WW physics and to properly define the signal versus the background. With appropriate kinematical cuts it has been shown that the neutral-current background can be made vanishingly small when the problem of determining the W-boson mass is addressed. The remaining background from the complete charge-current and mixed processes is again small but not completely negligible. A detailed discussion is performed on the validity of the most relevant approximations such as the double-resonant one. The inclusion of a final state QCD correction, in its naive form (NQCD), is discussed and various implementations are examined. (orig.)

  1. CEBAF cryogenic system design

    International Nuclear Information System (INIS)

    Rode, C.; Brindza, P.

    1986-01-01

    The Continuous Electron Beam Accelerator Facility (CEBAF) is a standing wave superconducting linear accelerator with a maximum energy of 4 GeV and 200 μA beam current. The 418 Cornell/CEBAF superconducting niobium accelerating cavities are arranged in two 0.5 GeV linacs with magnetic recirculating arcs at each end. There is one recirculating arc for each energy beam that is circulating and any three of the four correlated energies may be supplied to any of the three experimental halls. The cryogenics system for CEBAF consists of a 5kW central helium refrigerator and a transfer line system to supply 2.2 K 2.8 ATM helium to the cavity cryostats, 40 K helium at 3.5 ATM to the radiation shields and 4.5K helium at 2.8 ATM to the superconducting magnetic spectrometers in the experimental halls. Both the 2.2K and the 4.5K helium are expanded by Joule-Thompson (JT) valves in the individual cryostats yielding 2.0K at .031 ATM and 4.4K at 1.2 ATM respectively. The Central Helium Refrigerator is located in the center of the CEBAF racetrack with the transfer lines located in the linac tunnels

  2. Operation of large cryogenic systems

    International Nuclear Information System (INIS)

    Rode, C.H.; Ferry, B.; Fowler, W.B.; Makara, J.; Peterson, T.; Theilacker, J.; Walker, R.

    1985-06-01

    This report is based on the past 12 years of experiments on R and D and operation of the 27 kW Fermilab Tevatron Cryogenic System. In general the comments are applicable for all helium plants larger than 1000W (400 l/hr) and non mass-produced nitrogen plants larger than 50 tons per day. 14 refs., 3 figs., 1 tab

  3. Cryogenics safety

    International Nuclear Information System (INIS)

    Reider, R.

    1977-01-01

    The safety hazards associated with handling cryogenic fluids are discussed in detail. These hazards include pressure buildup when a cryogenic fluid is heated and becomes a gas, potential damage to body tissues due to surface contact, toxic risk from breathing air altered by cryogenic fluids, dangers of air solidification, and hazards of combustible cryogens such as liquified oxygen, hydrogen, or natural gas or of combustible mixtures. Safe operating procedures and emergency planning are described

  4. A breath of fresh air for cryogenics training

    CERN Multimedia

    HSE Unit

    2014-01-01

    Whether you work full-time in a cryogenic installation or are required to handle cryogenic substances temporarily, you need to have followed the appropriate safety training.   Photo: Christoph Balle. Two new training courses are now available in English and French at CERN: “Cryogenic Safety – Fundamentals” (at the Prévessin Training Centre) and “Cryogenic Safety – Helium Transfer” (at the Cryolab). The first covers the content of levels 1 and 2 of the old “Cryogenic Safety” course. The second is a completely new course for CERN: it covers specific aspects of the transfer of liquid helium, such as the evaporation process of helium and the associated risks to human health (asphyxia due to displacement of oxygen), the colour code for gas bottles, etc. These training modules have been rewritten in response to the increase in the number of projects involving cryogenics and following various related incident...

  5. Helium Extraction from LNG End Flash

    OpenAIRE

    Kim, Donghoi

    2014-01-01

    Helium is an invaluable element as it is widely used in industry such as cryo-genics and welding due to its unique properties. However, helium shortage is expected in near future because of increasing demand and the anxiety of sup-ply. Consequently, helium production has attracted the attention of industry. The main source of He is natural gas and extracting it from LNG end-flash is considered as the most promising way of producing crude helium. Thus, many process suppliers have proposed proc...

  6. Cryogenic exciter

    Science.gov (United States)

    Bray, James William [Niskayuna, NY; Garces, Luis Jose [Niskayuna, NY

    2012-03-13

    The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

  7. The Management of Cryogens at CERN

    CERN Document Server

    Delikaris, D; Passardi, Giorgio; Serio, L; Tavian, L

    2005-01-01

    CERN is a large user of industrially procured cryogens essentially liquid helium and nitrogen. Recent contracts have been placed by the Organization for the delivery of quantities up to 280 tons of liquid helium over four years and up to 50000 tons of liquid nitrogen over three years. Main users are the very large cryogenic system of the LHC accelerator complex, the physics experiments using superconducting magnets and liquefied gases and all the related test facilities whether industrial or laboratory scale. With the commissioning of LHC, the need of cryogens at CERN will considerably increase and the procurement policy must be adapted accordingly. In this paper, we discuss procurement strategy for liquid helium and nitrogen, including delivery rates, distribution methods and adopted safety standards. Global turnover, on site re-liquefaction capacity, operational consumption, accidental losses, purification means and storage capacity will be described. Finally, the short to medium term evolution of the Orga...

  8. Liquid helium

    CERN Document Server

    Atkins, K R

    1959-01-01

    Originally published in 1959 as part of the Cambridge Monographs on Physics series, this book addresses liquid helium from the dual perspectives of statistical mechanics and hydrodynamics. Atkins looks at both Helium Three and Helium Four, as well as the properties of a combination of the two isotopes. This book will be of value to anyone with an interest in the history of science and the study of one of the universe's most fundamental elements.

  9. A helium regenerative compressor

    International Nuclear Information System (INIS)

    Swift, W.L.; Nutt, W.E.; Sixsmith, H.

    1994-01-01

    This paper discusses the design and performance of a regenerative compressor that was developed primarily for use in cryogenic helium systems. The objectives for the development were to achieve acceptable efficiency in the machine using conventional motor and bearing technology while reducing the complexity of the system required to control contamination from the lubricants. A single stage compressor was built and tested. The compressor incorporates aerodynamically shaped blades on a 218 mm (8.6 inches) diameter impeller to achieve high efficiency. A gas-buffered non-contact shaft seal is used to oppose the diffusion of lubricant from the motor bearings into the cryogenic circuit. Since it is a rotating machine, the flow is continuous and steady, and the machine is very quiet. During performance testing with helium, the single stage machine has demonstrated a pressure ratio of 1.5 at a flow rate of 12 g/s with measured isothermal efficiencies in excess of 30%. This performance compares favorably with efficiencies generally achieved in oil flooded screw compressors

  10. COOLING STAGES OF CRYOGENIC SYSTEMS

    OpenAIRE

    Троценко, А. В.

    2011-01-01

    The formalized definition for cooling stage of low temperature system is done. Based on existing information about the known cryogenic unit cycles the possible types of cooling stages are single out. From analyses of these stages their classification by various characteristics is suggested. The results of thermodynamic optimization of final throttle stage of cooling, which are used as working fluids helium, hydrogen and nitrogen, are shown.

  11. Commissioning of cryogenic system for China Spallation Neutron Source

    Science.gov (United States)

    Ye, Bin; He, Chongchao; Li, Na; Ding, Meiying; Wang, Yaqiong; Yu, Zhang; He, Kun

    2017-12-01

    China Spallation Neutron Source(CSNS) cryogenic system provides supercritical cryogenic hydrogen to neutron moderators, including a helium refrigerator, hydrogen loop and hydrogen safety equipment. The helium refrigerator is provided by Linde with cooling capacity of 2200 W at 20 K. Hydrogen loop system mainly includes cryogenic hydrogen pipes, hydrogen circulator cold-box and accumulator cold-box. Cryogenic hydrogen pump, ortho-para convertor, helium-hydrogen heat-exchanger, hydrogen heater and accumulator are integrated in hydrogen circulation cold-box, and accumulator cold-box. Hydrogen safety equipment includes safety valves, rupture disk, hydrogen sensor, flame detector and other equipment to ensure that cryogenic system in dangerous situations will go down, vents, or takes other measures. The cryogenic system commissioning work includes four steps. First, in order to test the refrigerating capacity of refrigerator, when acceptance testing, refrigerator internal heater was used as thermal load. Second, using simulation load as heat load of moderator, hydrogen loop use helium instead of hydrogen, and cooled down to 20 K, then re-warming and test the leak detection of hydrogen loop system. Third, base on the step 2, using hydrogen as working medium, and optimized the control logic. Forth, cryogenic system with the moderators joint commissioning. Now, cryogenic system is connected with the moderators, and the forth step will be carried out in the near future.

  12. Thermodynamic properties of cryogenic fluids

    CERN Document Server

    Leachman, Jacob; Lemmon, Eric; Penoncello, Steven

    2017-01-01

    This update to a classic reference text provides practising engineers and scientists with accurate thermophysical property data for cryogenic fluids. The equations for fifteen important cryogenic fluids are presented in a basic format, accompanied by pressure-enthalpy and temperature-entropy charts and tables of thermodynamic properties. It begins with a chapter introducing the thermodynamic relations and functional forms for equations of state, and goes on to describe the requirements for thermodynamic property formulations, needed for the complete definition of the thermodynamic properties of a fluid. The core of the book comprises extensive data tables and charts for the most commonly-encountered cryogenic fluids. This new edition sees significant updates to the data presented for air, argon, carbon monoxide, deuterium, ethane, helium, hydrogen, krypton, nitrogen and xenon. The book supports and complements NIST’s REFPROP - an interactive database and tool for the calculation of thermodynamic propertie...

  13. The LHC cryogenic system and operational experience from the first three years run

    International Nuclear Information System (INIS)

    Delikaris, Dimitri; Tavian, Laurent

    2014-01-01

    The LHC (Large Hadron Collider) accelerator helium cryogenic system consists of eight cryogenically independent sectors, each 3.3 km long, all cooled and operated at 1.9 K. The overall, entropy equivalent, installed cryogenic capacity totalizes 144 kW (a) 4.5 K including 19.2 kW (a) 1.8 K with an associated helium inventory of 130 ton. The LHC cryogenic system is considered among the most complex and powerful in the world allowing the cooling down to superfluid helium temperature of 1.9 K. of the accelerators' high field superconducting magnets distributed over the 26.7 km underground ring. The present article describes the LHC cryogenic system and its associated cryogen infrastructure. Operational experience, including cryogen management, acquired from the first three years of LHC operation is finally presented. (author)

  14. Three-body decays of Higgs bosons at LEP2 and application to a hidden fermiophobic Higgs

    International Nuclear Information System (INIS)

    Akeroyd, A.G.

    1999-01-01

    We study the decays of Higgs bosons to a lighter Higgs boson and a virtual gauge boson in the context of the non-supersymmetric two-Higgs doublet model (2HDM). We consider the phenomenological impact at LEP2 and find that such decays, when open, may be dominant in regions of parameter space and thus affect current Higgs boson search techniques. Three-body decays would be a way of producing light neutral Higgs bosons which have so far escaped detection at LEP due to suppressed couplings to the Z, and are of particular importance in the 2HDM (Model I) which allows both a light fermiophobic Higgs and a light charged scalar

  15. Search for $\\gamma\\gamma \\rightarrow \\eta_b$ in $e^{+}e^{-}$ collisions at LEP2

    CERN Document Server

    Heister, A.; Barate, R.; Bruneliere, R.; De Bonis, I.; Decamp, D.; Goy, C.; Jezequel, S.; Lees, J.P.; Martin, F.; Merle, E.; Minard, M.N.; Pietrzyk, B.; Trocme, B.; Boix, G.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Grauges, E.; Lopez, J.; Martinez, M.; Merino, G.; Miquel, R.; Mir, Ll.M.; Pacheco, A.; Paneque, D.; Ruiz, H.; Colaleo, A.; Creanza, D.; De Filippis, N.; de Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Azzurri, P.; Barklow, T.; Buchmuller, O.; Cattaneo, M.; Cerutti, F.; Clerbaux, B.; Drevermann, H.; Forty, R.W.; Frank, M.; Gianotti, F.; Greening, T.C.; Hansen, J.B.; Harvey, J.; Hutchcroft, D.E.; Janot, P.; Jost, B.; Kado, M.; Mato, P.; Moutoussi, A.; Ranjard, F.; Rolandi, Gigi; Schlatter, D.; Sguazzoni, G.; Tejessy, W.; Teubert, F.; Valassi, A.; Videau, I.; Ward, J.J.; Badaud, F.; Dessagne, S.; Falvard, A.; Fayolle, D.; Gay, P.; Jousset, J.; Michel, B.; Monteil, S.; Pallin, D.; Pascolo, J.M.; Perret, P.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Nilsson, B.S.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Brient, J.C.; Machefert, F.; Rouge, A.; Swynghedauw, M.; Tanaka, R.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bossi, F.; Campana, P.; Capon, G.; Chiarella, V.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G.P.; Passalacqua, L.; Halley, A.; Kennedy, J.; Lynch, J.G.; Negus, P.; O'Shea, V.; Thompson, A.S.; Wasserbaech, S.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E.E.; Leibenguth, G.; Putzer, A.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Davies, G.; Dornan, P.J.; Girone, M.; Hill, R.D.; Marinelli, N.; Nowell, J.; Przysiezniak, H.; Rutherford, S.A.; Sedgbeer, J.K.; Thompson, J.C.; White, R.; Ghete, V.M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C.K.; Clarke, D.P.; Ellis, G.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Pearson, M.R.; Robertson, N.A.; Smizanska, M.; van der Aa, O.; Delaere, C.; Lemaitre, V.; Blumenschein, U.; Holldorfer, F.; Jakobs, K.; Kayser, F.; Kleinknecht, K.; Muller, A.S.; Quast, G.; Renk, B.; Sander, H.G.; Schmeling, S.; Wachsmuth, H.; Zeitnitz, C.; Ziegler, T.; Bonissent, A.; Coyle, P.; Curtil, C.; Ealet, A.; Fouchez, D.; Payre, P.; Tilquin, A.; Ragusa, F.; David, A.; Dietl, H.; Ganis, G.; Huttmann, K.; Lutjens, G.; Manner, W.; Moser, H.G.; Settles, R.; Wolf, G.; Boucrot, J.; Callot, O.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, P.; Jacholkowska, A.; Loomis, C.; Serin, L.; Veillet, J.J.; de Vivie de Regie, J.B.; Yuan, C.; Bagliesi, Giuseppe; Boccali, T.; Foa, L.; Giammanco, A.; Giassi, A.; Ligabue, F.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciaba, A.; Tenchini, R.; Venturi, A.; Verdini, P.G.; Awunor, O.; Blair, G.A.; Coles, J.; Cowan, G.; Garcia-Bellido, A.; Green, M.G.; Jones, L.T.; Medcalf, T.; Misiejuk, A.; Strong, J.A.; Teixeira-Dias, P.; Clifft, R.W.; Edgecock, T.R.; Norton, P.R.; Tomalin, I.R.; Bloch-Devaux, Brigitte; Boumediene, D.; Colas, P.; Fabbro, B.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.F.; Rosowsky, A.; Seager, P.; Trabelsi, A.; Tuchming, B.; Vallage, B.; Konstantinidis, N.; Litke, A.M.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Hodgson, P.N.; Lehto, M.; Thompson, L.F.; Affholderbach, K.; Boehrer, Armin; Brandt, S.; Grupen, C.; Hess, J.; Ngac, A.; Prange, G.; Sieler, U.; Borean, C.; Giannini, G.; He, H.; Putz, J.; Rothberg, J.; Armstrong, S.R.; Berkelman, Karl; Cranmer, K.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Hayes, O.J.; Hu, H.; Jin, S.; Kile, J.; McNamara, P.A., III; Nielsen, J.; Pan, Y.B.; von Wimmersperg-Toeller, J.H.; Wiedenmann, W.; Wu, J.; Wu, Sau Lan; Wu, X.; Zobernig, G.

    2002-01-01

    A search for the pseudoscalar meson eta_b is performed in two-photon interactions at LEP~2 with an integrated luminosity of 699 pb^-1 collected at e+e- centre-of-mass energies from 181 GeV to 209 GeV. One candidate event is found in the six-charged-particle final state and none in the four-charged-particle final state, in agreement with the total expected background of about one event. Upper limits of Gamma_gammagamma(eta_b) * BR(eta_b -> 4 charged particles) 6 charged particles) < 132 eV are obtained at 95\\% confidence level, which correspond to 95\\% confidence level upper limits of $9.0\\%$ and $25\\%$ on these branching ratios.

  16. Capacity enhancement of indigenous expansion engine based helium liquefier

    Science.gov (United States)

    Doohan, R. S.; Kush, P. K.; Maheshwari, G.

    2017-02-01

    Development of technology and understanding for large capacity helium refrigeration and liquefaction at helium temperature is indispensable for coming-up projects. A new version of helium liquefier designed and built to provide approximately 35 liters of liquid helium per hour. The refrigeration capacity of this reciprocating type expansion engine machine has been increased from its predecessor version with continuous improvement and deficiency debugging. The helium liquefier has been built using components by local industries including cryogenic Aluminum plate fin heat exchangers. Two compressors with nearly identical capacity have been deployed for the operation of system. Together they consume about 110 kW of electric power. The system employs liquid Nitrogen precooling to enhance liquid Helium yield. This paper describes details of the cryogenic expander design improvements, reconfiguration of heat exchangers, performance simulation and their experimental validation.

  17. The cryogenic control system of EAST

    International Nuclear Information System (INIS)

    Zhuang, M.; Hu, L.B.; Zhow, Z.W.; Xia, G.H.

    2012-01-01

    Highlights: ► A reliable and flexible duplex control system is required for cryogenic system. ► The cryogenic control system is based on Delta-V DCS. ► It has been proved to be an effective way to control cryogenic process. ► It will provide useful experience and inspiration for the development in the cryogenic control engineering. - Abstract: A large scale helium cryogenic system is one of the key components for the EAST tokamak device for the cooling of PF and TF coils, structures, thermal shields, buslines, current leads and cryopumps. Since the cooling scheme of the EAST cryogenic system is fairly complicated, a reliable and flexible control system is required for cryogenic system. The cryogenic control system is based on DeltaV DCS which is the process control software developed by Emerson Company. The EAST cryogenic system has been in operation for four years and has been proved to be safe, stable and energy saving by the past 7 experiments. This paper describes the redundant control network, hardware configuration, software structure, auxiliary system and the new development in the future.

  18. Superfluid helium at subcritical active core

    International Nuclear Information System (INIS)

    Vasil'ev, V.V.; Lopatkin, A.V.; Muratov, V.G.; Rakhno, I.L.

    2002-01-01

    Power range and neutron flux wherein super thermal source was realized at high volume of superfluid helium were investigated. MCU, BRAND, MCNP codes were used for the calculation of reactors. It is shown that the availability of full-size diameter for cryogenic source of ultracold neutrons, as the source with superfluid helium is considered, is possible in the reflector of subcritical assembly. Results obtained from the MCNP-4B code application demonstrated that the density of thermal neutron flux in helium must be not higher than 2.3 x 10 11 s -1 cm -2 [ru

  19. Helium refrigeration system for hydrogen liquefaction applications

    Science.gov (United States)

    Nair, J. Kumar, Sr.; Menon, RS; Goyal, M.; Ansari, NA; Chakravarty, A.; Joemon, V.

    2017-02-01

    Liquid hydrogen around 20 K is used as cold moderator for generating “cold neutron beam” in nuclear research reactors. A cryogenic helium refrigeration system is the core upon which such hydrogen liquefaction applications are built. A thermodynamic process based on reversed Brayton cycle with two stage expansion using high speed cryogenic turboexpanders (TEX) along with a pair of compact high effectiveness process heat exchangers (HX), is well suited for such applications. An existing helium refrigeration system, which had earlier demonstrated a refrigeration capacity of 470 W at around 20 K, is modified based on past operational experiences and newer application requirements. Modifications include addition of a new heat exchanger to simulate cryogenic process load and two other heat exchangers for controlling the temperatures of helium streams leading out to the application system. To incorporate these changes, cryogenic piping inside the cold box is suitably modified. This paper presents process simulation, sizing of new heat exchangers as well as fabrication aspects of the modified cryogenic process piping.

  20. Cryogenic infrastructure for Fermilab's ILC vertical cavity test facility

    International Nuclear Information System (INIS)

    Carcagno, R.; Ginsburg, C.; Huang, Y.; Norris, B.; Ozelis, J.; Peterson, T.; Poloubotko, V.; Rabehl, R.; Sylvester, C.; Wong, M.; Fermilab

    2006-01-01

    Fermilab is building a Vertical Cavity Test Facility (VCTF) to provide for R and D and pre-production testing of bare 9-cell, 1.3-GHz superconducting RF (SRF) cavities for the International Linear Collider (ILC) program. This facility is located in the existing Industrial Building 1 (IB1) where the Magnet Test Facility (MTF) also resides. Helium and nitrogen cryogenics are shared between the VCTF and MTF including the existing 1500-W at 4.5-K helium refrigerator with vacuum pumping for super-fluid operation (125-W capacity at 2-K). The VCTF is being constructed in multiple phases. The first phase is scheduled for completion in mid 2007, and includes modifications to the IB1 cryogenic infrastructure to allow helium cooling to be directed to either the VCTF or MTF as scheduling demands require. At this stage, the VCTF consists of one Vertical Test Stand (VTS) cryostat for the testing of one cavity in a 2-K helium bath. Planning is underway to provide a total of three Vertical Test Stands at VCTF, each capable of accommodating two cavities. Cryogenic infrastructure improvements necessary to support these additional VCTF test stands include a dedicated ambient temperature vacuum pump, a new helium purification skid, and the addition of helium gas storage. This paper describes the system design and initial cryogenic operation results for the first VCTF phase, and outlines future cryogenic infrastructure upgrade plans for expanding to three Vertical Test Stands

  1. CRYOGENIC INFRASTRUCTURE FOR FERMILAB'S ILC VERTICAL CAVITY TEST FACILITY

    International Nuclear Information System (INIS)

    Carcagno, R.; Ginsburg, C.; Huang, Y.; Norris, B.; Ozelis, J.; Peterson, T.; Poloubotko, V.; Rabehl, R.; Sylvester, C.; Wong, M.

    2008-01-01

    Fermilab is building a Vertical Cavity Test Facility (VCTF) to provide for R and D and pre-production testing of bare 9-cell, 1.3-GHz superconducting RF (SRF) cavities for the International Linear Collider (ILC) program. This facility is located in the existing Industrial Building 1 (IB1) where the Magnet Test Facility (MTF) also resides. Helium and nitrogen cryogenics are shared between the VCTF and MTF including the existing 1500-W at 4.5-K helium refrigerator with vacuum pumping for super-fluid operation (125-W capacity at 2-K). The VCTF is being constructed in multiple phases. The first phase is scheduled for completion in mid 2007, and includes modifications to the IB1 cryogenic infrastructure to allow helium cooling to be directed to either the VCTF or MTF as scheduling demands require. At this stage, the VCTF consists of one Vertical Test Stand (VTS) cryostat for the testing of one cavity in a 2-K helium bath. Planning is underway to provide a total of three Vertical Test Stands at VCTF, each capable of accommodating two cavities. Cryogenic infrastructure improvements necessary to support these additional VCTF test stands include a dedicated ambient temperature vacuum pump, a new helium purification skid, and the addition of helium gas storage. This paper describes the system design and initial cryogenic operation results for the first VCTF phase, and outlines future cryogenic infrastructure upgrade plans for expanding to three Vertical Test Stands

  2. Booster cryogenics

    International Nuclear Information System (INIS)

    Storm, D.W.; Weitkamp, W.G.; Will, D.I.

    1984-01-01

    During this past year the authors have ordered a helium refrigerator, developed cryostat specifications and come to understand better some of the potential problems to avoid in helium distribution systems. The helium refrigerator consists of a Koch Process Systems 2800HR with three type RS screw compressors. The 2800HR has two dry expansion engines, each with two 3'' diameter pistons, and one wet expansion engine with a single 2'' diameter piston. It has guaranteed capacities at 4.5 0 K of 440 W without liquid nitrogen precool and of 510 W with liquid nitrogen precool which compare favorably with the estimated need of 300 W. At present the authors have nearly completed material, technique and performance specifications for their cryostats, pending a decision on bayonet design, and the authors are beginning preliminary specifications for their liquid helium distribution manifold and transfer siphons

  3. Cryogenics '88

    International Nuclear Information System (INIS)

    1988-04-01

    The proceedings has four chapters: Processes and apparatus of low-temperature installations, Superconductors and magnets, Gas separators, Helium liquefiers and cryostats. It contains a total of 56 papers of which 4 belong in the INIS scope. (J.B.)

  4. Photoionization of helium dimers

    International Nuclear Information System (INIS)

    Havermeier, Tilo

    2010-01-01

    The helium dimer is one of the most weakly bound systems in the universe. This makes it an interesting quantum mechanical object for investigation. These Van der Waals Clusters can be produced in an expansion of a cryogenic gas jet through a small nozzle into vacuum. In the present experiment we examine the interaction of He dimers with synchrotron radiation at an energy range from 64 to 78 eV. We observed different pathways leading to single ionization of both He atoms of the dimer compound. This two close standing ions begin now to dissociate in cause of their coulomb potential. All charged fragments were detected in coincidence with a COLTRIMS system. Especially Interatomic Coulombic Decay (ICD) and the two step process (TS1) were clearly identified. Furthermore a distribution of the internuclear distance was obtained from the measured Kinetic Energy Release (KER). (orig.)

  5. Thermal Stabilization of Cryogenic System in Superconducting Cyclotron

    International Nuclear Information System (INIS)

    Shin, Seung Jae; Kim, Kyung Min; Cho, Hyung Hee; Hong, Bong Hwan; Kang, Joon Sun; Ahn, Dong Hyun

    2011-01-01

    Radiology has some useful applications for medical purpose. For cancer therapy, the superconducting cyclotron should generate heavy ion beams. It radiates heavy ion beams to cancer patients. In order to make cyclotron system stable, the cryogenic system which makes superconducting state should work constantly. However, radiation heat transfer of cryogenic system should be considered because liquid helium's boiling point is extremely low and there is huge temperature difference between the cryogenic system and ambient temperature. Accordingly, thermal analysis should be carried out. In this paper, the numerical analysis of the cryogenic system in practical superconducting cyclotron show temperature distribution and suggest the number of coolers using ANSYS Workbench program

  6. Search for standard and non-minimal Higgs boson at LEP2 with the L3 detector

    International Nuclear Information System (INIS)

    Teyssier, Daniel

    2002-01-01

    This thesis worked out in the frame of L3 collaboration - Higgs working group refers to the search for a Higgs signature, for center-of-mass energies between 192 and 209 GeV, one of the main goals of LEP2. It consists of a contribution to the analyses looking for the Standard Model Higgs boson, especially in the so-called 'two jets plus missing energy' channel. The final state of this channel, denoted H νν -bar, is characterized by the production of a pair of b quarks, from the decay of the Higgs particle, and a neutrino pair from that of the Z particle, for the prevalent Higgs-Strahlung process. The lower observed mass limit, obtained with the H νν -bar channel alone, is 96 GeV at a 95% confidence level. In addition, searches for neutral scalar particle production are presented, in the context of general two-Higgs-doublet models of type II, by means of a so-called 'flavor independent' analysis. Searches for 'invisible' Higgs bosons are presented as well, with the Z boson decaying into a pair of fermions while the Higgs boson decays into undetectable particles. These results permit constraining the parameters of the minimal non-universal supersymmetric models (without gaugino mass unification). (author)

  7. Search for Higgs Boson in the channel with missing energy with the detector ALEPH at LEP2

    International Nuclear Information System (INIS)

    Kado, Marumi

    1999-01-01

    A search for the Standard Model Higgs boson in the channel e + e - → Hνν-bar is presented. An event selection method using Neural Network techniques is developed. The analysis is based on a 254 pb -1 data sample taken at center-of-mass energies from √ s = 161 up to 189 GeV (from 1996 to 1998), by the ALEPH detector within the LEP2 program at CERN. The experimental systematic defects are studied and the corrections and uncertainties are evaluated. The study of this channel alone results in a mass lower limit of the Standard Model Higgs boson of 85.8 GeV/c 2 with a sensitivity of 89 GeV/c 2 at the 95% CL. Combined with all studied final states, the limit at 95% CL obtained is: m H > 90.2 GeV/c 2 (observed) and m H > 95.7 GeV/c 2 (expected). An interpolation of these results within the Minimal Supersymmetric Standard Model is presented along with the combination of all channels, including those originating from the associated production process (e + e - → hA, leading to an exclusion at the 95% CL, for any value of tanβ≥ 1, of the h and A neutral Higgs boson masses of: m H > 80.1 GeV/c 2 (observed) and m A > 81.7 GeV/c 2 (observed). (author)

  8. Search for Higgs Boson in the channel with missing energy with the detector ALEPH at LEP2; Recherche du Boson de Higgs dans le canal a energie manquante avec le detecteur ALEPH a LEP2

    Energy Technology Data Exchange (ETDEWEB)

    Kado, Marumi [Paris-6 Univ., 95 Paris (France)

    1999-04-20

    A search for the Standard Model Higgs boson in the channel e{sup +}e{sup -} {yields} H{nu}{nu}-bar is presented. An event selection method using Neural Network techniques is developed. The analysis is based on a 254 pb{sup -1} data sample taken at center-of-mass energies from {radical} s = 161 up to 189 GeV (from 1996 to 1998), by the ALEPH detector within the LEP2 program at CERN. The experimental systematic defects are studied and the corrections and uncertainties are evaluated. The study of this channel alone results in a mass lower limit of the Standard Model Higgs boson of 85.8 GeV/c{sup 2} with a sensitivity of 89 GeV/c{sup 2} at the 95% CL. Combined with all studied final states, the limit at 95% CL obtained is: m{sub H} > 90.2 GeV/c{sup 2} (observed) and m{sub H} > 95.7 GeV/c{sup 2} (expected). An interpolation of these results within the Minimal Supersymmetric Standard Model is presented along with the combination of all channels, including those originating from the associated production process (e{sup +}e{sup -} {yields} hA), leading to an exclusion at the 95% CL, for any value of tan{beta}{>=} 1, of the h and A neutral Higgs boson masses of: m{sub H} > 80.1 GeV/c{sup 2} (observed) and m{sub A} > 81.7 GeV/c{sup 2} (observed). (author)

  9. StructUre and test results of the Tokamak-7 device cryogenic system

    International Nuclear Information System (INIS)

    Babaev, I.V.; VolobUev, A.N.; Zhul'kin, V.F.

    1982-01-01

    A cryogenic system (CS) of the Tokamak-7 (T-7) installation with the longitudinal field superconducting magnetic system (SMS) is described. The CS is designed for cool-down, cryostatic cooling and heating of the T-7 cryogenic objects and consists of a helium system (HS) and a nitrogen cryogenic system (NCS). The HS consists of:a a heliUm delivery system intended for distributing and controlling the helium flows in the SMS; cryogenic helium units; a 1.25 m 3 volume for storing liquid helium; a compressor compartment using piston compressors at the 3 MPa operating pressure and 140 g/s total capacity; gaseous helium storages (3600 m 3 under normal conditions); helium cleaning and drying systems; a gas holder of 20 m 3 operating volume; cryogenic pipelines and pipe fittings. The NCS operates on delivered nitrogen and includes a 120 m 3 liquid nitrogen storage, evaporators and electric heaters producing up to 230 g/s of gaseous nitrogen at 300 K, a separator, cryogenic pipelines and fittings. It is found that the CS has the necessary cold production reserve, ensures reliable operation of the Tokamak-7 device and permits to carry out practically continuous plasma experiments

  10. KSTAR Helium Refrigeration System Design and Manufacturing

    International Nuclear Information System (INIS)

    Dauguet, P.; Briend, P.; Abe, I.; Fauve, E.; Bernhardt, J.-M.; Andrieu, F.; Beauvisage, J.

    2006-01-01

    The tokamak developed in the KSTAR (Korean Superconducting Tokamak Advanced Research) project makes intensive use of superconducting magnets operated at 4.5 K. The cold components of the KSTAR tokamak require forced flow of supercritical helium for magnets/structure, boiling liquid helium for current leads, and gaseous helium for thermal shields. The cryogenic system will provide stable operation and full automatic control. A three-pressure helium cycle composed of six turbines has been customised design for this project. The '' design '' operating mode results with a system composed of a 9 kW refrigerator (including safety margin) and using gas and liquid storages for mass balancing. During Shot/Standby mode, the heat loads are highly time-dependent. A thermal damper is used to smooth these variations and will allow stable operation. (author)

  11. The Cryogenic Storage Ring CSR

    OpenAIRE

    von Hahn, Robert; Becker, Arno; Berg, Felix; Blaum, Klaus; Breitenfeldt, Christian; Fadil, Hisham; Fellenberger, Florian; Froese, Michael; George, Sebastian; Göck, Jürgen; Grieser, Manfred; Grussie, Florian; Guerin, Elisabeth A.; Heber, Oded; Herwig, Philipp

    2016-01-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion a...

  12. Cryogenics; Criogenia

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez R, C; Jimenez D, J; Cejudo A, J; Hernandez M, V [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    Cryogenics is one of these technologies which contributes to scientific research that supports to the industry in the following benefits: 1. Storage ability and a great quantity of dense gases with cryogenic liquid which is found at high pressure. 2. Production ability at low cost with high purity gases through distillation or condensation. 3. Ability to use low temperatures in the refrigerating materials or alteration of the physical properties. This technology is used for reprocessing of those short and long half life radioactive wastes which always have been required that to be separated with classical methods. In this text we report the radioactive wastes separation by more sophisticated methods but more quickly and reliable. (Author)

  13. Cryogenic regenerators

    International Nuclear Information System (INIS)

    Kush, P.; Joshi, S.C.; Thirumaleshwar, M.

    1986-01-01

    Importance of regenerators in cryogenic refrigerators is highlighted. Design aspects of regenerator are reviewed and the factors involved in the selection of regenerator material are enumerated. Various methods used to calculate the heat transfer coefficient and regenerator effectiveness are mentioned. Variation of effectiveness with various parameters is calculated by a computer programme using the ideal, Ackermann and Tipler formulae. Results are presented in graphical form. Listing of the computer programme is given in the Appendix. (author)

  14. Computer automation of a dilution cryogenic system

    International Nuclear Information System (INIS)

    Nogues, C.

    1992-09-01

    This study has been realized in the framework of studies on developing new technic for low temperature detectors for neutrinos and dark matter. The principles of low temperature physics and helium 4 and dilution cryostats, are first reviewed. The cryogenic system used and the technic for low temperature thermometry and regulation systems are then described. The computer automation of the dilution cryogenic system involves: numerical measurement of the parameter set (pressure, temperature, flow rate); computer assisted operating of the cryostat and the pump bench; numerical regulation of pressure and temperature; operation sequence full automation allowing the system to evolve from a state to another (temperature descent for example)

  15. Cryogenic test facility at VECC, Kolkata

    International Nuclear Information System (INIS)

    Sarkar, Amit; Bhunia, Uttam; Pradhan, J.; Sur, A.; Bhandari, R.K.; Ranganathan, R.

    2003-01-01

    In view of proposed K-500 superconducting cyclotron project, cryogenic test facility has been set up at the centre. The facility can broadly be categorized into two- a small scale test facility and a large scale test facility. This facility has been utilized for the calibration of liquid helium level probe, cryogenic temperature probe, and I-B plot for a 7 T superconducting magnet. Spiral-shaped superconducting short sample with specific dimension and specially designed stainless steel sample holder has already been developed for the electrical characterisation. The 1/5 th model superconducting coil along with its quench detection circuit and dump resistor has also been developed

  16. Cryogenic system for the HERA magnet measurement facility

    International Nuclear Information System (INIS)

    Barton, H.R. Jr.; Clausen, M.; Kebler, G.

    1986-01-01

    This paper describes the design for a helium, cryogenic distribution system that allows independent operation and testing of superconducting magnets of the HERA project before they are installed in the 6-km ring tunnel. The 820-GeV proton storage ring of HERA will contain approximately 650 magnets having superconducting coils which are clamped by aluminum/stainless-steel collars and surrounded by a yoke of magnetic iron at liquid helium temperature. When the magnets arive at DESY from the manufacture, each magnet will be individually tested at helium operating conditions in the magnet measurement facility to insure the quality of the magnetic characteristics and the cryogenic performance. The capabilities of the cryogenic system and the schedule for magnet testing are discussed

  17. Cryogenic equipment

    International Nuclear Information System (INIS)

    Leger, L.; Javellaud, J.; Caro, C.; Gilguy, R.; Testard, O.

    1966-06-01

    The cryostats presented here were built from standard parts; this makes it possible to construct a great variety of apparatus at minimum cost. The liquid nitrogen and helium reservoirs were designed so as to reduce losses to a minimum, and so as to make the cryostats as autonomous as possible. The experimental enclosure which is generally placed in the lower part of the apparatus requires a separate study in every case. Furthermore, complete assemblies such as transfer rods, isolated traps and high vacuum valves, were designed with a similar regard for the economic aspects and for the need for standardization. This equipment thus satisfies a great variety of experimental needs; it is readily adaptable and the consumptions of helium and liquid nitrogen are very low. (authors) [fr

  18. Cryogen free low temperature sample environment for neutron scattering experiments

    International Nuclear Information System (INIS)

    Kirichek, O; Evans, B E; Down, R B E; Bowden, Z A

    2009-01-01

    Recent increase in liquid helium cost caused by global helium supply problems rose significant concern about affordability of conventional cryogenic equipment. Luckily the progress in cryo-cooler technology offers a new generation of cryogenic systems with significantly reduced consumption and in some cases nearly complete elimination of cryogens. These cryogen-free systems also offer the advantage of operational simplicity and require less space than conventional cryogen-cooled systems. The ISIS facility carries on an internal development program intended to substitute gradually all conventional cryogenic systems with cryogen free systems preferably based on pulse tube refrigerators. A unique feature of this cryo-cooler is the absence of cold moving parts. This considerably reduces vibrations and increases the reliability of the cold head. The program includes few development projects which are aiming to deliver range of cryogen free equipment including top-loading cryostat, superconducting magnets and dilution refrigerators. Here we are going to describe the design of these systems and discuss the results of prototypes testing.

  19. Cryogenic turbulence

    CERN Document Server

    CERN. Geneva. Audiovisual Unit

    2005-01-01

    Understanding turbulence is vital in astrophysics, geophysics and many engineering applications, with thermal convection playing a central role. I shall describe progress that has recently been made in understanding this ubiquitous phenomenon by making controlled experiments using low-temperature helium, and a brief account of the frontier topic of superfluid turbulence will also be given. CERN might be able to play a unique role in experiments to probe these two problems.

  20. The European Graduate Course in Cryogenics hosted at CERN.

    CERN Multimedia

    Laurent Tavian

    2010-01-01

    The “liquid helium” week of the European Graduate Course in Cryogenics was held at CERN from 30 August to 3 September 2010. This course scheduled annually since 2008 is a common teaching project of the Universities of Technology of Dresden, Wroclaw and Trondheim. It is focused on liquid natural gas, hydrogen and helium cryogenics. Attending students were carefully selected, and will take an examination giving ECTS credits for their academic curriculum.   This year, as Wroclaw University of Technology was already heavily involved in organising the International Cryogenic Engineering Conference (ICEC), it requested that the “liquid helium” week to be exceptionally held at CERN. While this is certainly a good choice from the point of view of large cryogenic helium systems, with the large cryoplants cooling the Large Hadron Collider (LHC) and its experiments, CERN has only acted as host laboratory organizing the course classes and visits, and the teaching and i...

  1. Renovation of the Sissi cryogenic system

    International Nuclear Information System (INIS)

    Anon.

    1999-01-01

    SISSI (high current superconductor secondary ion source) involved a cryo-generator operating in a close circuit when the whole system was put in service in 1994. Since then the cryo-generator has proved to be insufficiently reliable. A new cryogenic system based on an external liquid helium supply has been designed. The helium transfer lines are surrounded by a shield at liquid nitrogen temperature and numerous layers of super-insulators in order to have minimum thermal losses. The installation was integrated to SISSI in summer 1998 and after the first operating period some improvements concerning the cooling procedure have to be considered. (A.C.)

  2. Cryogenic photodetectors

    Science.gov (United States)

    Chardin, G.

    2000-03-01

    Some of the most significant developments in cryogenic photodetectors are presented. In particular, the main characteristics of microbolometers involving Transition Edge- and NTD-sensors and offering resolutions of a few eV in the keV range, superconducting tunnel junction detectors with resolutions of the order of 10 eV or offering position sensitivity, and infrared bolometers with recent developments towards matrix detectors are discussed. Some of the recent achievements using large mass bolometers for gamma and neutron discriminating detectors, and future prospects of single photon detection in the far infrared using Single Electron Transistor devices are also presented.

  3. Cryogenic photodetectors

    CERN Document Server

    Chardin, G

    2000-01-01

    Some of the most significant developments in cryogenic photodetectors are presented. In particular, the main characteristics of microbolometers involving Transition Edge- and NTD-sensors and offering resolutions of a few eV in the keV range, superconducting tunnel junction detectors with resolutions of the order of 10 eV or offering position sensitivity, and infrared bolometers with recent developments towards matrix detectors are discussed. Some of the recent achievements using large mass bolometers for gamma and neutron discriminating detectors, and future prospects of single photon detection in the far infrared using Single Electron Transistor devices are also presented.

  4. Cryogenic aspects of the mirror fusion test facility

    International Nuclear Information System (INIS)

    Sterbentz, W.H.; Nelson, R.L.

    1979-01-01

    This paper covers the design and construction of the MFTF cryogenic system and a description of the operating procedures throughout the many functional modes. The coils and the cryopanels for maintaining the high vacuum environment weigh 417,000 kg (920,000 lb) and must be cooled from room temperature to 4.5 k. The cryogenic system for MFTF consists of a closed-loop helium system with a 3000-W helium refrigerator that uses gas-bearing expansion turbines and oil-flooded screw compressors. In addition, liquid helium storage facilities have adequate capacity for standby operation, and a complete helium-purification plant is capable of processing 17 m 3 /min (600 scfm). An open-loop liquid nitrogen system (with provision for later addition of a nitrogen recondenser) provides the required refrigeration for the radiation shields that must be maintained at 85 K

  5. Cryogenic laboratory (80 K - 4 K)

    International Nuclear Information System (INIS)

    Brad, Sebastian; Steflea, Dumitru

    2002-01-01

    The technology of low temperature at the beginning of this century, developed for the production of oxygen, nitrogen and rare gases, was the basis for setting up the cryogenic technology in all the companies with these activity fields. The cryogenics section of today comprises engineering and construction of cryogenic plants for science, research and development, space technology, nuclear power techniques. Linde has designed and built a reliable small scale Helium liquefier. This fully automatic cryoliquefier operates for purification, liquefaction as well as re-liquefaction of Helium-gas, evaporated in cryostat systems. The basic equipment of the Linde L5 are the liquefier apparatus, transfer line, medium pressure buffer vessel, automatic purifier, compressor with mechanical oil separation unit, oil adsorber, electrical control unit. The accessories of the Linde L5 are the liquid helium storage tank, high-pressure gas supply, helium recovery unit, and cryocomponents. The cycle compressor C 101 designed as a single stage screw compressor supplies the liquefaction process with approx. 10 g/s of helium at a pressure of 10 to 12 bar and a temperature of approx. 300 K. In the first plate heat exchanger E 201 the gas is cooled down to approx. 70 K. Then the He high-pressure flow is divided: about 7 g/s reach the turbine X 201 via valve 203 (turbine entry) and are expanded there to approx. 4.6 bar, the gas cooling down to 64 K. After further cooling in the heat exchanger E 203 to about 16 K, another power-consuming expansion to 1.2 bar takes place. The implied cooling of the gas results in a temperature of 12 K at the outlet of the turbine X 202. This gas is then transferred to the low-pressure side of the heat exchanger E 204. The smaller part of the He high-pressure gas flow (approx. 3 g/s) is cooled down in the heat exchanger E 202 - E 205 to about 7 K. One part of the cold helium gas (approx. 0.17 g/s) is used in the purifier to cool down the feed gas to air

  6. Cryogenic systems for the Mirror Fusion Test Facility

    International Nuclear Information System (INIS)

    Slack, D.S.; Nelson, R.L.; Chronis, W.C.

    1985-08-01

    This paper includes an in-depth discussion of the design, fabrication, and operation of the Mirror Fusion Test Facility (MFTF) cryogenic system located at Lawrence Livermore National Laboratory (LLNL). Each subsystem discussed to present a basic composite of the entire facility. The following subsystems are included: 500kW nitrogen reliquefier, subcoolers, and distribution system; 15kW helium refrigerator/liquefier and distribution system; helium recovery and storage system; rough vacuum and high vacuum systems

  7. Helium crystals

    International Nuclear Information System (INIS)

    Lipson, S.G.

    1987-01-01

    Hexagonal close-packed helium crystals in equilibrium with superfluid have been found to be one of the few systems in which an anisotropic solid comes into true thermodynamic equilibrium with its melt. The discovery of roughening transitions at the liquid-solid interface have shown this system to be ideal for the study of the statistical mechanics of interface structures. We describe the effect of roughening on the shape and growth of macroscopic crystals from both the theoretical and experimental points of view. (author)

  8. Helium-flow measurement using ultrasonic technique

    International Nuclear Information System (INIS)

    Sondericker, J.H.

    1983-01-01

    While designing cryogenic instrumentation for the Colliding Beam Accelerator (CBA) helium-distribution system it became clear that accurate measurement of mass flow of helium which varied in temperature from room to sub-cooled conditions would be difficult. Conventional venturi flow meters full scale differential pressure signal would decrease by more than an order of magnitude during cooldown causing unacceptable error at operating temperature. At sub-cooled temperatures, helium would be pumped around cooling loops by an efficient, low head pressure circulating compressor. Additional pressure drop meant more pump work was necessary to compress the fluid resulting in a higher outlet temperature. The ideal mass flowmeter for this application was one which did not add pressure drop to the system, functioned over the entire temperature range, has high resolution and delivers accurate mass flow measurement data. Ultrasonic flow measurement techniques used successfully by the process industry, seemed to meet all the necessary requirements. An extensive search for a supplier of such a device found that none of the commercial stock flowmeters were adaptable to cryogenic service so the development of the instrument was undertaken by the CBA Cryogenic Control and Instrumentation Engineering Group at BNL

  9. Cryogenic system for TRISTAN superconducting RF cavities

    International Nuclear Information System (INIS)

    Hosoyama, K.; Hara, K.; Kabe, A.; Kojima, Y.; Ogitsu, T.; Sakamoto, Y.; Kawamura, S.; Matsumoto, K.

    1993-01-01

    A large cryogenic system has been designed, constructed and operated in the TRISTAN electron-positron collider at KEK for 508 MHz, 32x5-cell superconducting RF cavities. A 6.5 kW, 4.4 K helium refrigerator with 5 turbo-expanders on the ground level supplies liquid helium in parallel to the 16 cryostats in the TRISTAN tunnel through about 250 m long multichannel transfer line. Two 5-cell cavities are coupled together, enclosed in a cryostat and cooled by about 830 L pool boiling liquid helium. A liquid nitrogen circulation system with a turbo-expander has been adopted for 80 K radiation shields in the multichannel transfer line and the cryostats to reduce liquid nitrogen consumption and to increase the operation stability of the system. The cryogenic system has a total of about 18 000 hours of operating time from the first cool down test in August 1988 to November 1991. The design principle and outline of the cryogenic system and the operational experience are presented. (orig.)

  10. Room temperature cryogenic test interface

    International Nuclear Information System (INIS)

    Faris, S. M.; Davidson, A.; Moskowitz, P. A.; Sai-Halasz, G. A.

    1985-01-01

    This interface permits the testing of high speed semiconductor devices (room-temperature chips) by a Josephson junction sampling device (cryogenic chip) without intolerable loss of resolution. The interface comprises a quartz pass-through plug which includes a planar transmission line interconnecting a first chip station, where the cryogenic chip is mounted, and a second chip station, where the semiconductor chip to be tested is temporarily mounted. The pass-through plug has a cemented long half-cylindrical portion and short half-cylindrical portion. The long portion carries the planar transmission line, the ends of which form the first and second chip mounting stations. The short portion completes the cylinder with the long portion for part of its length, where a seal can be achieved, but does not extend over the chip mounting stations. Sealing is by epoxy cement. The pass-through plug is sealed in place in a flange mounted to the chamber wall. The first chip station, with the cryogenic chip attached, extends into the liquid helium reservoir. The second chip station is in the room temperature environment required for semiconductor operation. Proper semiconductor operating temperature is achieved by a heater wire and control thermocouple in the vicinity of each other and the second chip mounting station. Thermal isolation is maintained by vacuum and seals. Connections for power and control, for test result signals, for temperature control and heating, and for vacuum complete the test apparatus

  11. Cryogenics for Particle Accelerators and Detectors

    CERN Document Server

    Lebrun, P; Vandoni, Giovanna; Wagner, U

    2002-01-01

    Cryogenics has become a key ancillary technology of particle accelerators and detectors, contributing to their sustained development over the last fifty years. Conversely, this development has produced new challenges and markets for cryogenics, resulting in a fruitful symbiotic relation which materialized in significant technology transfer and technical progress. This began with the use of liquid hydrogen and deuterium in the targets and bubble chambers of the 1950s, 1960s and 1970s. It developed more recently with increasing amounts of liquefied noble gases - mainly argon, but also krypton and even today xenon - in calorimeters. In parallel with these applications, the availability of practical type II superconductors from the early 1960s triggered the use of superconductivity in large spectrometer magnets - mostly driven by considerations of energy savings - and the corresponding development of helium cryogenics. It is however the generalized application of superconductivity in particle accelerators - RF ac...

  12. Termination for a superconducting power transmission line including a horizontal cryogenic bushing

    Science.gov (United States)

    Minati, Kurt F.; Morgan, Gerry H.; McNerney, Andrew J.; Schauer, Felix

    1984-01-01

    A termination for a superconducting power transmission line is disclosed which is comprised of a standard air entrance insulated vertical bushing with an elbow, a horizontal cryogenic bushing linking the pressurized cryogenic cable environment to the ambient temperature bushing and a stress cone which terminates the cable outer shield and transforms the large radial voltage gradient in the cable dielectric into a much lower radial voltage gradient in the high density helium coolant at the cold end of the cryogenic bushing.

  13. Cryogenic testing of the TPC superconducting solenoid

    International Nuclear Information System (INIS)

    Green, M.A.; Smits, R.G.; Taylor, J.D.

    1983-06-01

    This report describes the results of a series of tests on the TPC superconducting magnet cryogenic system which occurred during the winter and spring of 1983. The tests occurred at interaction region 2 of the PEP colliding beam facility at the Stanford Linear Accelerator Center (SLAC). The TPC Magnet Cryogenic System which was tested includes the following major components: a remote helium compressor with a full flow liquid nitrogen purification station, 400 meters of high pressure supply and low pressure return lines; and locally a CTi Model 2800 refrigerator with two Sulzer gas bearing turbines, the TPC magnet control dewar, 70 meters of transfer lines, and the TPC thin superconducting solenoid magnet. In addition, there is a conditioner (liquid nitrogen heat exchangers and gas heaters) system for cooldown and warmup of the magnet. This report describes the local cryogenic system and describes the various steps in the cooldown and operation of the TPC magnet. The tests were successful in that they showed that the TPC magnet could be cooled down in 24 hours and the magnet could be operated on the refrigerator or a helium pump with adequate cooling margin. The tests identified problems with the cryogenic system and the 2800 refrigerator. Procedures for successful operation and quenching of the superconducting magnet were developed. 19 references

  14. LDR cryogenics

    Science.gov (United States)

    Nast, T.

    1988-01-01

    A brief summary from the 1985 Large Deployable Reflector (LDR) Asilomar 2 workshop of the requirements for LDR cryogenic cooling is presented. The heat rates are simply the sum of the individual heat rates from the instruments. Consideration of duty cycle will have a dramatic effect on cooling requirements. There are many possible combinations of cooling techniques for each of the three temperatures zones. It is clear that much further system study is needed to determine what type of cooling system is required (He-2, hybrid or mechanical) and what size and power is required. As the instruments, along with their duty cycles and heat rates, become better defined it will be possible to better determine the optimum cooling systems.

  15. QCD corrections to $e^{+} e^{-} \\to u \\overline {d} s \\overline {c}$ at LEP 2 and the Next Linear Collider CC11 at O $\\alpha_{s}$

    CERN Document Server

    Maina, E; Pizzio, M

    1998-01-01

    QCD one-loop corrections to the full gauge invariant set of electroweak diagrams describing the hadronic process $e^+ e^- \\to u~\\bar d~s~\\bar c$ are computed. Four-jet shape variables for $WW$ events are studied at next-to-leading order and the effects of QCD corrections on the determination of the $W$--mass in the hadronic channel at Lep 2 and NLC is discussed. We compare the exact calculation with a ``naive''approach to strong radiative corrections which has been widely used in the literature.

  16. Sonic Helium Detectors in the Fermilab Tevatron

    Science.gov (United States)

    Bossert, R. J.

    2006-04-01

    In the Fermilab Tevatron cryogenic system there are many remotely located low-pressure plate relief valves that must vent large volumes of cold helium gas when magnet quenches occur. These valves can occasionally stick open or not reseat completely, resulting in a large helium loss. As such, the need exists for a detector to monitor the relief valve's discharge area for the presence of helium. Due to the quantity needed, cost is an important factor. A unit has been developed and built for this purpose that is quite inexpensive. Its operating principle is based on the speed of sound, where two closely matched tubes operate at their acoustic resonant frequency. When helium is introduced into one of these tubes, the resulting difference in acoustic time of flight is used to trigger an alarm. At present, there are 39 of these units installed and operating in the Tevatron. They have detected many minor and major helium leaks, and have also been found useful in detecting a rise in the helium background in the enclosed refrigerator buildings. This paper covers the construction, usage and operational experience gained with these units over the last several years.

  17. Sonic helium detectors in the Fermilab Tevatron

    International Nuclear Information System (INIS)

    Bossert, R.J.; Fermilab

    2006-01-01

    In the Fermilab Tevatron cryogenic system there are many remotely located low-pressure plate relief valves that must vent large volumes of cold helium gas when magnet quenches occur. These valves can occasionally stick open or not reseat completely, resulting in a large helium loss. As such, the need exists for a detector to monitor the relief valve's discharge area for the presence of helium. Due to the quantity needed, cost is an important factor. A unit has been developed and built for this purpose that is quite inexpensive. Its operating principle is based on the speed of sound, where two closely matched tubes operate at their acoustic resonant frequency. When helium is introduced into one of these tubes, the resulting difference in acoustic time of flight is used to trigger an alarm. At present, there are 39 of these units installed and operating in the Tevatron. They have detected many minor and major helium leaks, and have also been found useful in detecting a rise in the helium background in the enclosed refrigerator buildings. This paper covers the construction, usage and operational experience gained with these units over the last several years

  18. Separation of compressor oil from helium

    International Nuclear Information System (INIS)

    Strauss, R.; Perrotta, K.A.

    1982-01-01

    Compression of helium by an oil-sealed rorary screw compressor entrains as much as 4000 parts per million by weight of liquid and vapor oil impurities in the gas. The reduction below about 0.1 ppm for cryogenic applications is discussed. Oil seperation equipment designed for compressed air must be modified significantly to produce the desired results with helium. The main differences between air and helium filtration are described. A description of the coalescers is given with the continuous coalescing of liquid mist from air or other gas illustrated. Oil vapor in helium is discussed in terms of typical compressor oils, experimental procedure for measuring oil vapor concentration, measured volatile hydrocarbons in the lubricants, and calculated concentration of oil vapor in Helium. Liquid oil contamination in helium gas can be reduced well below 0.1 ppm by a properly designed multiple state coalescing filter system containing graded efficiency filter elements. The oil vapor problem is best attached by efficiently treating the oil to remove most of the colatiles before charging the compressor

  19. Advances in cryogenic engineering. Volume 27 - Proceedings of the Cryogenic Engineering Conference, San Diego, CA, August 11-14, 1981

    Science.gov (United States)

    Fast, R. W.

    Applications of superconductivity are considered, taking into account MHD and fusion, generators, transformers, transmission lines, magnets for physics, cryogenic techniques, electrtronics, and aspects of magnet stability. Advances related to heat transfer in He I are discussed along with subjects related to theat transfer in He II, refrigeration of superconducting systems, refrigeration and liquefaction, dilution and magnetic refrigerators, refrigerators for space applications, mass transfer and flow phenomena, and the properties of fluids. Developments related to cryogenic applications are also explored, giving attention to bulk storage and transfer of cryogenic fluids, liquefied natural gas operations, space science and technology, and cryopumping. Topics related to cryogenic instrumentation and controls include the production and use of high grade silicon diode temperature sensors, the choice of strain gages for use in a large superconducting alternator, microprocessor control of cryogenic pressure, and instrumentation, data acquisition and reduction for a large spaceborne helium dewar. For individual items see A83-43221 to A83-43250

  20. High Reynolds number flows using liquid and gaseous helium

    International Nuclear Information System (INIS)

    Donnelly, R.J.

    1991-01-01

    Consideration is given to liquid and gaseous helium as test fluids, high Reynolds number test requirements in low speed aerodynamics, the measurement of subsonic flow around an appended body of revolution at cryogenic conditions in the NTF, water tunnels, flow visualization, the six component magnetic suspension system for wind tunnel testing, and recent aerodynamic measurements with magnetic suspension systems. Attention is also given to application of a flow visualization technique to a superflow experiment, experimental investigations of He II flows at high Reynolds numbers, a study of homogeneous turbulence in superfluid helium, and thermal convection in liquid helium

  1. The Future with Cryogenic Fluid Dynamics

    Science.gov (United States)

    Scurlock, R. G.

    The applications of cryogenic systems have expanded over the past 50 years into many areas of our lives. During this time, the impact of the common features of Cryogenic Fluid Dynamics, CryoFD, on the economic design of these cryogenic systems, has grown out of a long series of experimental studies carried out by teams of postgraduate students at Southampton University.These studies have sought to understand the heat transfer and convective behavior of cryogenic liquids and vapors, but they have only skimmed over the many findings made, on the strong convective motions of fluids at low temperatures. The convection takes place in temperature gradients up to 10,000 K per meter, and density gradients of 1000% per meter and more, with rapid temperature and spatially dependent changes in physical properties like viscosity and surface tension, making software development and empirical correlations almost impossible to achieve. These temperature and density gradients are far larger than those met in other convecting systems at ambient temperatures, and there is little similarity. The paper will discuss the likely impact of CryoFD on future cryogenic systems, and hopefully inspire further research to support and expand the use of existing findings, and to improve the economy of present-day systems even more effectively. Particular examples to be mentioned include the following. Doubling the cooling power of cryo-coolers by a simple use of CryoFD. Reducing the boil-off rate of liquid helium stored at the South Pole, such that liquid helium availability is now all-the-year-round. Helping to develop the 15 kA current leads for the LHC superconducting magnets at CERN, with much reduced refrigeration loads. Improving the heat transfer capability of boiling heat transfer surfaces by 10 to 100 fold. This paper is an edited text of an invited plenary presentation at ICEC25/ICMC2014 by Professor Scurlock on the occasion of his being presented with the ICEC Mendelssohn Award for his

  2. Pair production of Z and W polarization at LEP2 determined with ALEPH detector or Prolegomena to any future apparently complete study on gauge bosons

    International Nuclear Information System (INIS)

    Fayolle, David

    2002-01-01

    The start of LEP2 at centre of mass energies higher then the W-pair production threshold, has made possible for the first time to test the least bounded sector of the Standard Model, the bosonic sector. This thesis consists in three strong measurements of the validity of the Standard Model using the whole LEP2 data set recorded by the ALEPH detector: - The measurement of the ZZ cross section through the five visible decay channels of the Z-pair. The poor statistic associated to pair production of Z is a process difficult to discriminate - The measurement of the anomalous neutral gauge couplings in tile ZZ final state. These couplings are forbidden in the Standard Model and their existence would be the signature of a New Physics. The information on the cross section as well as the angular distribution of the Z is used to extract them. - The measurement of the longitudinal and transverse polarised states of the W bosons through the W + W - production in the semi-leptonic channel. The spin density matrix method is used because it introduces a 'model independent' framework. No deviation is observed with respect to the Standard Model predictions. (author)

  3. Re-Condensation and Liquefaction of Helium and Hydrogen Using Coolers

    International Nuclear Information System (INIS)

    Green, Michael A.

    2009-01-01

    Coolers are used to cool cryogen free devices at temperatures from 5 to 30 K. Cryogen free cooling involves a temperature drop within the device being cooled and between the device and the cooler cold heads. Liquid cooling with a liquid cryogen distributed over the surface of a device combined with re-condensation can result in a much lower temperature drop between the cooler and the device being cooled. The next logical step beyond simple re-condensation is using a cooler to liquefy the liquid cryogen in the device. A number of tests of helium liquefaction and re-condensation of helium have been run using a pulse tube cooler in the drop-in mode. This report discusses the parameter space over which re-condensation and liquefaction for helium and hydrogen can occur.

  4. Cryogenic infrastructure for Fermilab's ILC vertical cavity test facility

    Energy Technology Data Exchange (ETDEWEB)

    Carcagno, R.; Ginsburg, C.; Huang, Y.; Norris, B.; Ozelis, J.; Peterson, T.; Poloubotko, V.; Rabehl, R.; Sylvester, C.; Wong, M.; /Fermilab

    2006-06-01

    Fermilab is building a Vertical Cavity Test Facility (VCTF) to provide for R&D and pre-production testing of bare 9-cell, 1.3-GHz superconducting RF (SRF) cavities for the International Linear Collider (ILC) program. This facility is located in the existing Industrial Building 1 (IB1) where the Magnet Test Facility (MTF) also resides. Helium and nitrogen cryogenics are shared between the VCTF and MTF including the existing 1500-W at 4.5-K helium refrigerator with vacuum pumping for super-fluid operation (125-W capacity at 2-K). The VCTF is being constructed in multiple phases. The first phase is scheduled for completion in mid 2007, and includes modifications to the IB1 cryogenic infrastructure to allow helium cooling to be directed to either the VCTF or MTF as scheduling demands require. At this stage, the VCTF consists of one Vertical Test Stand (VTS) cryostat for the testing of one cavity in a 2-K helium bath. Planning is underway to provide a total of three Vertical Test Stands at VCTF, each capable of accommodating two cavities. Cryogenic infrastructure improvements necessary to support these additional VCTF test stands include a dedicated ambient temperature vacuum pump, a new helium purification skid, and the addition of helium gas storage. This paper describes the system design and initial cryogenic operation results for the first VCTF phase, and outlines future cryogenic infrastructure upgrade plans for expanding to three Vertical Test Stands.

  5. Cryogenic detectors

    International Nuclear Information System (INIS)

    Zehnder, A.

    1987-01-01

    Presently the development of new large scale detector systems, used in very high energy physics experiments, is very active. In the low energy range, the introduction of charge coupled devices allows improved spacial and energy resolution. In the keV region, high resolution can only be achieved via the well established diffraction spectrometers with the well-known disadvantage of a small throughput. There exist no efficient detectors for non-ionizing radiation such as coherent nuclear scattering of weakly interacting particles. The development of high resolution solid state detectors in the keV-region with the possibility of nuclear recoil detection is therefore highly desired. Such detectors applied in astro and particle physics would thus allow one to obtain new information not achievable otherwise. Three types of cryogenic detectors exist: Calorimeters/Bolometers. This type is sensitive to the produced excess phonons and measures the deposited energy by detecting the heat pulses. Excess charge carriers should be used to produce phonons. Tunneling junctions. This type is sensitive to excess charge produced by the Cooper pair breakup. Excess phonons should be used to break up Cooper pairs. Superheated superconducting granules (SSG). An SSG detector consists of granules, the metastability of which is disturbed by radiation. The Meissner effect then causes a change in the field distribution of the applied external field, which can be detected. The present paper discusses the basic principle of calorimetric and tunneling junction detectors and some of their applications. 26 refs., 7 figs., 1 tab

  6. Numerical study of emergency cryogenics gas relief into confined spaces

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    The presented work focuses on the risk analysis and the consequences of the unexpected leak to the tunnel of cryogenics gases. Formation of the gas mixture and its propagation along tunnels is an important issue for the safe operation of cryogenic machines, including superconducting accelerators or free electron lasers. As the cryogenics gas the helium and argon will be considered. A minimal numerical model will be presented and discussed. Series of numerical results related to emergency helium relief to the CERN tunnel and related to unexpected leak of the argon to an underground tunnel, will be shown. The numerical results will show temperature distribution, oxygen deficiency and gas cloud propagation in function of intensity of the leak and intensity of the ventilation.

  7. Characterizing Dissolved Gases in Cryogenic Liquid Fuels

    Science.gov (United States)

    Richardson, Ian A.

    Pressure-Density-Temperature-Composition (PrhoT-x) measurements of cryogenic fuel mixtures are a historical challenge due to the difficulties of maintaining cryogenic temperatures and precision isolation of a mixture sample. For decades NASA has used helium to pressurize liquid hydrogen propellant tanks to maintain tank pressure and reduce boil off. This process causes helium gas to dissolve into liquid hydrogen creating a cryogenic mixture with thermodynamic properties that vary from pure liquid hydrogen. This can lead to inefficiencies in fuel storage and instabilities in fluid flow. As NASA plans for longer missions to Mars and beyond, small inefficiencies such as dissolved helium in liquid propellant become significant. Traditional NASA models are unable to account for dissolved helium due to a lack of fundamental property measurements necessary for the development of a mixture Equation Of State (EOS). The first PrhoT-x measurements of helium-hydrogen mixtures using a retrofitted single-sinker densimeter, magnetic suspension microbalance, and calibrated gas chromatograph are presented in this research. These measurements were used to develop the first multi-phase EOS for helium-hydrogen mixtures which was implemented into NASA's Generalized Fluid System Simulation Program (GFSSP) to determine the significance of mixture non-idealities. It was revealed that having dissolved helium in the propellant does not have a significant effect on the tank pressurization rate but does affect the rate at which the propellant temperature rises. PrhoT-x measurements are conducted on methane-ethane mixtures with dissolved nitrogen gas to simulate the conditions of the hydrocarbon seas of Saturn's moon Titan. Titan is the only known celestial body in the solar system besides Earth with stable liquid seas accessible on the surface. The PrhoT-x measurements are used to develop solubility models to aid in the design of the Titan Submarine. NASA is currently designing the submarine

  8. Functional Analysis of the Distribution Box of the KSTAR Helium Refrigerator

    International Nuclear Information System (INIS)

    Chang, H. S.; Kim, Y. S.; Bak, J. S.

    2005-01-01

    KSTAR (Korea Superconducting Tokamak Advanced Research) is a tokamak device with 30 superconducting (SC) magnet coils. The main duty of the KSTAR helium refrigerator is to keep all cold components of KSTAR (SC magnet coils, magnet structures, SC bus-lines, current lead system, and thermal shields) at suitable temperatures in order to operate the SC magnet coils consistent with the operation scenario of KSTAR. A distribution box (D/B) which is equipped with helium-property-measuring sensors, cryogenic valves (CV's), cryogenic circulators, and heat exchangers (HX's) submerged in a huge liquid helium (LHe) bath (thermal damper), intervenes the cryogenic helium via cryogenic transfer lines (TL's) between the refrigerator cold box (C/B) and the KSTAR cold components. The major functions of the D/B can be classified as listed below: i) Supplying the proper cryogen to the respective cold components of KSTAR during various operation modes (including the idle mode). ii) Cool/re-cool down of the KSTAR cold components from any temperature down to their operating cryogenic temperature within the constraints of time and temperature difference between the components. iii) Protection of the KSTAR cold components and refrigerator from damaging in case of probable abnormal events. iv) Simulation of the temporal variation of the thermal load and pressure drops occurring in the KSTAR cold components to pre-commission the refrigerator and test the cryogenic circulators. v) SC coil/bus-line cable-in-conduit conductor (CICC) cleaning. Since the helium flow in the thermal shields (TS's) is rather routine and the current lead (CL) system has its own helium distribution system, in this proceeding mainly the supercritical helium (SHe) circuits of the SC magnets and bus-lines will be discussed

  9. Energy Efficient Cryogenics

    Science.gov (United States)

    Meneghelli, Barry J.; Notardonato, William; Fesmire, James E.

    2016-01-01

    The Cryogenics Test Laboratory, NASA Kennedy Space Center, works to provide practical solutions to low-temperature problems while focusing on long-term technology targets for the energy-efficient use of cryogenics on Earth and in space.

  10. Cryogenics a textbook

    CERN Document Server

    Thipse, S S

    2013-01-01

    A Textbook covers lucidly various cryogenic applications including cryogenic engines and space and electronic applications. Importance of cryogenic engines in space propulsion, complete thermodynamic analysis of cryogenic systems with special emphasis on cryogenic cycles, Dewar vessels used to store cryogenic fluids and their applications in various industries have also been discussed in detail. Explanation of Superconductivity and its applications with a description of various Cryocoolers used in industry has also been provided with extensive details. Further technical information on cryogens has been specified alongwith the vacuum technology which has been sufficiently described with examples. Science of Cryonics has been elaborated and all aspects of technology related to functioning of cryogenic plants and their construction including valves, pipes has been incorporated in this book.

  11. Cryogenic system for VECC K500 superconducting cyclotron

    CERN Document Server

    Pal, G; Bhattacharyya, T K; Bhandari, R K

    2009-01-01

    VEC Centre, Kolkata in India is at an advanced stage of commissioning a K500 superconducting cyclotron. The superconducting coil of the magnet for cyclotron is cooled by liquid helium. Three liquid helium cooled cryopanels, placed inside the Dees of the radiofrequency system, maintain the vacuum in the acceleration region of the superconducting cyclotron. The cryogenic system for magnet for cyclotron has been tested by cooling the coil and energizing the magnet. The cryogenic system for cryopanels has also been tested. Heater and temperature sensor were placed on the liquid helium cold head for cryopanel. The temperature of the cold head was observed to be below 20 K upto a heat load of 11.7 watt.

  12. Cryogenic system of the nuclotron - a new superconducting synchrotron

    International Nuclear Information System (INIS)

    Baldin, A.M.; Agapov, N.N.; Belushkin, V.A.; D'yachkov, E.I.; Khodzhibagiyan, H.G.; Kovalenko, A.D.; Makarov, L.G.; Matyushevsky, E.A.; Smirnov, A.A.

    1994-01-01

    The superconducting relativistic heavy ion accelerator was commissioned the last week of March in Dubna, and the first deuteron beam was circulated in the ring. The total cold mass of the magnetic system is about 80 tons. The magnet with a open-quotes coldclose quotes iron yoke and a hollow superconductor winding is refrigerated by a two-phase helium flow. All 160 magnets are connected in parallel with supply and return helium headers about 250 meters long. The cryogenic supply system is based on three helium refrigerators with a total capacity of 4.8 kW at 4.5 K. The results on the commissioning of the cryogenic system are presented

  13. Cryogenic system of the nuclotron - a new superconducting synchrotron

    International Nuclear Information System (INIS)

    Baldin, A.M.; Agapov, N.N.; Belushkin, V.A.

    1993-01-01

    The superconducting relativistic heavy ion accelerator was commissioned the last week of March in Dubna, and the first deuteron beam was circulated in the ring. The total cold mass of the magnetic system is about 80 tons. The magnet with a 'cold' iron yoke and a hollow superconductor winding is refrigerated by a two-phase helium flow. All 160 magnets are connected in parallel with supply and return helium headers about 250 meters long. The cryogenic supply system is based on three helium refrigerators with a total capacity of 4.8 kW at 4.5 K. The results on the commissioning of the cryogenic system are presented. 11 refs.; 5 figs.; 1 tab

  14. Cryogenic immersion microscope

    Science.gov (United States)

    Le Gros, Mark; Larabell, Carolyn A.

    2010-12-14

    A cryogenic immersion microscope whose objective lens is at least partially in contact with a liquid reservoir of a cryogenic liquid, in which reservoir a sample of interest is immersed is disclosed. When the cryogenic liquid has an index of refraction that reduces refraction at interfaces between the lens and the sample, overall resolution and image quality are improved. A combination of an immersion microscope and x-ray microscope, suitable for imaging at cryogenic temperatures is also disclosed.

  15. Helium hammer in superfluid transfer

    Science.gov (United States)

    Tward, E.; Mason, P. V.

    1984-01-01

    Large transient pressure pulses, referred to as a helium hammer, which occurred in the transfer line of the main cryogenic tank during the development tests of the Infrared Astronomical Satellite, launched on January 25, 1983, are analyzed, and the measures taken to prevent a failure described. The modifications include an installation of a 2.3-liter surge tank upstream, and a back-up relief valve downstream, of a burst disk. The surge tank is designed to attenuate a 0.33-MPa pressure pulse at the inlet down to 0.092 MPa at the outlet. A mechanism of the pulse generation is suggested, which involves flashing and rapid recondensation of the small amount of liquid entering the warm section of a transition to room temperature.

  16. The DIII-D cryogenic system upgrade

    International Nuclear Information System (INIS)

    Schaubel, K.M.; Laughon, G.J.; Campbell, G.L.; Langhorn, A.R.; Stevens, N.C.; Tupper, M.L.

    1993-10-01

    The original DIII-D cryogenic system was commissioned in 1981 and was used to cool the cryopanel arrays for three hydrogen neutral beam injectors. Since then, new demands for liquid helium have arisen including: a fourth neutral beam injector, ten superconducting magnets for the electron cyclotron heating gyrotrons, and more recently, the advanced diverter cryopump which resides inside the tokamak vacuum vessel. The original cryosystem could not meet these demands. Consequently, the cryosystem was upgraded in several phases to increase capacity, improve reliability, and reduce maintenance. The majority of the original system has been replaced with superior equipment. The capacity now exists to support present as well as future demands for liquid helium at DIII-D including a hydrogen pellet injector, which is being constructed by Oak Ridge National Laboratory. Upgrades to the cryosystem include: a recently commissioned 150 ell/hr helium liquefier, two 55 g/sec helium screw compressors, a fully automated 20-valve cryogen distribution box, a high efficiency helium wet expander, and the conversion of equipment from manual or pneumatic to programmable logic controller (PLC) control. The distribution box was designed and constructed for compactness due to limited space availability. Overall system efficiency was significantly improved by replacing the existing neutral beam reliquefier Joule-Thomson valve with a reciprocating wet expander. The implementation of a PLC-based automatic control system has resulted in increased efficiency and reliability. This paper will describe the cryosystem design with emphasis on newly added equipment. In addition, performance and operational experience will be discussed

  17. The DIII-D cryogenic system upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Schaubel, K.M.; Laughon, G.J.; Campbell, G.L.; Langhorn, A.R.; Stevens, N.C.; Tupper, M.L.

    1993-10-01

    The original DIII-D cryogenic system was commissioned in 1981 and was used to cool the cryopanel arrays for three hydrogen neutral beam injectors. Since then, new demands for liquid helium have arisen including: a fourth neutral beam injector, ten superconducting magnets for the electron cyclotron heating gyrotrons, and more recently, the advanced diverter cryopump which resides inside the tokamak vacuum vessel. The original cryosystem could not meet these demands. Consequently, the cryosystem was upgraded in several phases to increase capacity, improve reliability, and reduce maintenance. The majority of the original system has been replaced with superior equipment. The capacity now exists to support present as well as future demands for liquid helium at DIII-D including a hydrogen pellet injector, which is being constructed by Oak Ridge National Laboratory. Upgrades to the cryosystem include: a recently commissioned 150 {ell}/hr helium liquefier, two 55 g/sec helium screw compressors, a fully automated 20-valve cryogen distribution box, a high efficiency helium wet expander, and the conversion of equipment from manual or pneumatic to programmable logic controller (PLC) control. The distribution box was designed and constructed for compactness due to limited space availability. Overall system efficiency was significantly improved by replacing the existing neutral beam reliquefier Joule-Thomson valve with a reciprocating wet expander. The implementation of a PLC-based automatic control system has resulted in increased efficiency and reliability. This paper will describe the cryosystem design with emphasis on newly added equipment. In addition, performance and operational experience will be discussed.

  18. Cryogen Safety Course 8876

    Energy Technology Data Exchange (ETDEWEB)

    Glass, George [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-13

    Cryogenics (from the Greek word κρvoζ, meaning frost or icy cold) is the study of the behavior of matter at very cold temperatures. The purpose of this course is to provide trainees with an introduction to cryogen use, the hazards and potential accidents related to cryogen systems, cryogen safety components, and the requirements that govern the design and use of cryogen systems at Los Alamos National Laboratory (LANL). The knowledge you gain will help you keep your workplace safe for yourself and your coworkers.

  19. Cryogenic heat transfer

    CERN Document Server

    Barron, Randall F

    2016-01-01

    Cryogenic Heat Transfer, Second Edition continues to address specific heat transfer problems that occur in the cryogenic temperature range where there are distinct differences from conventional heat transfer problems. This updated version examines the use of computer-aided design in cryogenic engineering and emphasizes commonly used computer programs to address modern cryogenic heat transfer problems. It introduces additional topics in cryogenic heat transfer that include latent heat expressions; lumped-capacity transient heat transfer; thermal stresses; Laplace transform solutions; oscillating flow heat transfer, and computer-aided heat exchanger design. It also includes new examples and homework problems throughout the book, and provides ample references for further study.

  20. The cryogenic storage ring CSR

    Science.gov (United States)

    von Hahn, R.; Becker, A.; Berg, F.; Blaum, K.; Breitenfeldt, C.; Fadil, H.; Fellenberger, F.; Froese, M.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; Heber, O.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lange, M.; Laux, F.; Lohmann, S.; Menk, S.; Meyer, C.; Mishra, P. M.; Novotný, O.; O'Connor, A. P.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Saurabh, S.; Schippers, S.; Schröter, C. D.; Schwalm, D.; Schweikhard, L.; Sieber, T.; Shornikov, A.; Spruck, K.; Sunil Kumar, S.; Ullrich, J.; Urbain, X.; Vogel, S.; Wilhelm, P.; Wolf, A.; Zajfman, D.

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm-3 is derived, equivalent to a room-temperature pressure below 10-14 mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  1. The cryogenic storage ring CSR.

    Science.gov (United States)

    von Hahn, R; Becker, A; Berg, F; Blaum, K; Breitenfeldt, C; Fadil, H; Fellenberger, F; Froese, M; George, S; Göck, J; Grieser, M; Grussie, F; Guerin, E A; Heber, O; Herwig, P; Karthein, J; Krantz, C; Kreckel, H; Lange, M; Laux, F; Lohmann, S; Menk, S; Meyer, C; Mishra, P M; Novotný, O; O'Connor, A P; Orlov, D A; Rappaport, M L; Repnow, R; Saurabh, S; Schippers, S; Schröter, C D; Schwalm, D; Schweikhard, L; Sieber, T; Shornikov, A; Spruck, K; Sunil Kumar, S; Ullrich, J; Urbain, X; Vogel, S; Wilhelm, P; Wolf, A; Zajfman, D

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm(-3) is derived, equivalent to a room-temperature pressure below 10(-14) mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  2. The cryogenic storage ring CSR

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, R. von; Becker, A.; Berg, F.; Blaum, K.; Fadil, H.; Fellenberger, F.; Froese, M.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lange, M.; Laux, F.; Lohmann, S.; Menk, S. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); and others

    2016-06-15

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm{sup −3} is derived, equivalent to a room-temperature pressure below 10{sup −14} mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  3. Search for charged Higgs bosons and measurement of |V sub c sub s | in quark and lepton flavour identified events at LEP2

    CERN Document Server

    Kiiskinen, A P

    1999-01-01

    A search for pair produced charged Higgs bosons was performed on the high energy data collected by DELPHI at LEP2. All three major final states, tau nu tau nu, cs tau nu and cscs were searched for. The analyses used a combination of event shape variables, di-jet masses and jet flavour tagging. The jet flavours were identified by using life time tagging and particle identification based on the RICH detector complemented by ionisation energy loss measurements. A similar type of jet flavour tagging was also used in extracting the |V sub c sub s | element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix in hadronic decays of the W sup+- boson.

  4. Cryogenic system design for a compact tokamak reactor

    International Nuclear Information System (INIS)

    Slack, D.S.; Kerns, J.A.; Miller, J.R.

    1988-01-01

    The International Tokamak Engineering Reactor (ITER) is a program presently underway to design a next-generation tokamak reactor. The cryogenic system for this reactor must meet unusual and new requirements. Unusually high heat loads (100 kW at 4.5 K) must be handled because neutron shielding has been limited to save space in the reactor core. Also, large variations in the cryogenics loads occur over short periods of time because of the pulsed nature of some of the operating scenarios. This paper describes a workable cryogenic system design for a compact tokamak reactor such as ITER. A design analysis is presented dealing with a system that handles transient loads, coil quenches, reactor cool-down and the effect of variations in helium-supply temperatures on the cryogenic stability of the coils. 5 refs., 4 figs., 1 tab

  5. Search for Higgs Boson of Minimal Standard Model in the hadronic final states with the detector ALEPH at LEP 2; Recherche du boson de Higgs du Modele Standard Minimal dans les etats finals hadroniques avec le detecteur ALEPH a LEP 2

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, Olivier [Lab. de Physique Corpusculaire, Clermont-Ferrand-2 Univ., 63 - Aubiere (France)

    1999-04-16

    In the Standard Model framework of the particle physics the mass of fermions and electroweak gauge boson mass is related to a scalar sector. In the Minimal Version of the Standard Model, a neutral scalar particle is predicted: the Higgs boson. Its mass is a free parameter of the model. The search for this boson has been actively performed at the LEP collider and it has been extended by the recent increase of its energy (LEP 2). In addition, due to the increase of the signal to background ratio at LEP 2, the data analysis has been extended to new channels. This is particularly the case of the dominant, HZ {yields} hadrons, channel leading to 65% of the e{sup +}e{sup -} {yields} HZ production process final states at LEP. The aim of the work presented in this document, is the search of the Minimal Standard Model Higgs boson in the fully hadronic final state data recorded by the ALEPH detector at LEP 2 energies. A selection tool based on an artificial neural network multi-variate method, has been developed in order to separate the signal process from known Standard Model background processes. The neural network method allows to combine non-linearly the information describing the signal, and to reach performances better than those obtained by classical method based on cuts. No evidence of signal has been seen in the data collected by ALEPH up to {radical}s = 189 GeV. Thirty-two candidates has been selected in agreement with the 26.3 events expected for the background processes. Combining all channels from Higgs boson search, the limit m{sub H} > 90.2 GeV/c{sup 2} is obtained with a 95% confidence level. (author)

  6. Simulation of ideal-gas flow by nitrogen and other selected gases at cryogenic temperatures. [transonic flow in cryogenic wind tunnels

    Science.gov (United States)

    Hall, R. M.; Adcock, J. B.

    1981-01-01

    The real gas behavior of nitrogen, the gas normally used in transonic cryogenic tunnels, is reported for the following flow processes: isentropic expansion, normal shocks, boundary layers, and interactions between shock waves and boundary layers. The only difference in predicted pressure ratio between nitrogen and an ideal gas which may limit the minimum operating temperature of transonic cryogenic wind tunnels occur at total pressures approaching 9 atm and total temperatures 10 K below the corresponding saturation temperature. These pressure differences approach 1 percent for both isentropic expansions and normal shocks. Alternative cryogenic test gases were also analyzed. Differences between air and an ideal diatomic gas are similar in magnitude to those for nitrogen and should present no difficulty. However, differences for helium and hydrogen are over an order of magnitude greater than those for nitrogen or air. It is concluded that helium and cryogenic hydrogen would not approximate the compressible flow of an ideal diatomic gas.

  7. Thermal-hydraulic optimization of flexible transfer lines for liquid helium; Thermohydraulische Optimierung flexibler Transferleitungen fuer Fluessighelium

    Energy Technology Data Exchange (ETDEWEB)

    Dittmar, Nico; Haberstroh, Christoph; Hesse, U. [Technische Univ. Dresden (Germany). Bitzer-Stiftungsprofessur fuer Kaelte-, Kryo- und Kompressorentechnik; Wolfram, M.; Krzyzowski, M.; Raccanelli, A. [CryoVac Gesellschaft fuer Tieftemperaturtechnik mbH und Co. KG, Troisdorf (Germany)

    2014-07-01

    Cooling systems and applications at very low temperatures are based on the use of liquid helium as cryogenic agent; the normal boiling temperature of helium-4 is 4.2 K. Due to the restricted economic production possibilities and the high energetic expenditure for helium liquefaction an efficient and sustainable handling with the resources is recommended. In university facilities the liquid helium is usually stored in containers and filled into smaller containers for transport using cryogenic transfer lines. This procedure can cause 20% loss by evaporation due to heat input and friction pressure losses. The gaseous helium has to be collected for re-liquefaction. The contribution shows that using systematic measurements an increase of the transfer rate and the efficiency of the helium filling system can be reached by a modified transfer line design.

  8. The Cryogenic Supervision System in NSRRC

    CERN Document Server

    Li, Hsing-Chieh; Chiou, Wen-Song; Hsiao, Feng-Zone; Tsai, Zong-Da

    2005-01-01

    The helium cryogenic system in NSRRC is a fully automatic PLC system using the Siemens SIMATIC 300 controller. Modularization in both hardware and software makes it easy in the program reading, the system modification and the problem debug. Based on the Laview program we had developed a supervision system taking advantage of the Internet technology to get system's real-time information in any place. The functions of this supervision system include the real-time data accessing with more than 300 digital/analog signals, the data restore, the history trend display, and the human machine interface. The data is accessed via a Profibus line connecting the PLC system and the supervision system with a maximum baud rate 1.5 Mbit/s. Due to this supervision system, it is easy to master the status of the cryogenic system within a short time and diagnose the problem.

  9. Characterization of titanium alloys for cryogenic applications

    International Nuclear Information System (INIS)

    Reytier, M.; Kircher, F.; Levesy, B.

    2002-01-01

    Titanium alloys are employed in the design of superconducting magnet support systems for their high mechanical strength associated with their low thermal conductivity. But their use requires a careful attention to their crack tolerance at cryogenic temperature. Measurements have been performed on two extra low interstitial materials (Ti-5Al-2.5Sn ELI and Ti-6Al-4V ELI) with different thickness and manufacturing process. The investigation includes the tensile properties at room and liquid helium temperatures using smooth and notched samples. Moreover, the fracture toughness has been determined at 4.2 K using Compact Tension specimens. The microstructure of the different alloys and the various fracture surfaces have also been studied. After a detailed description of the experimental procedures, practical engineering characteristics are given and a comparison of the different titanium alloys is proposed for cryogenic applications

  10. Cryogenic Fluid Management Technology for Moon and Mars Missions

    Science.gov (United States)

    Doherty, Michael P.; Gaby, Joseph D.; Salerno, Louis J.; Sutherlin, Steven G.

    2010-01-01

    In support of the U.S. Space Exploration Policy, focused cryogenic fluid management technology efforts are underway within the National Aeronautics and Space Administration. Under the auspices of the Exploration Technology Development Program, cryogenic fluid management technology efforts are being conducted by the Cryogenic Fluid Management Project. Cryogenic Fluid Management Project objectives are to develop storage, transfer, and handling technologies for cryogens to support high performance demands of lunar, and ultimately, Mars missions in the application areas of propulsion, surface systems, and Earth-based ground operations. The targeted use of cryogens and cryogenic technologies for these application areas is anticipated to significantly reduce propellant launch mass and required on-orbit margins, to reduce and even eliminate storage tank boil-off losses for long term missions, to economize ground pad storage and transfer operations, and to expand operational and architectural operations at destination. This paper organizes Cryogenic Fluid Management Project technology efforts according to Exploration Architecture target areas, and discusses the scope of trade studies, analytical modeling, and test efforts presently underway, as well as future plans, to address those target areas. The target areas are: liquid methane/liquid oxygen for propelling the Altair Lander Ascent Stage, liquid hydrogen/liquid oxygen for propelling the Altair Lander Descent Stage and Ares V Earth Departure Stage, liquefaction, zero boil-off, and propellant scavenging for Lunar Surface Systems, cold helium and zero boil-off technologies for Earth-Based Ground Operations, and architecture definition studies for long term storage and on-orbit transfer and pressurization of LH2, cryogenic Mars landing and ascent vehicles, and cryogenic production via in situ resource utilization on Mars.

  11. Forced two phase helium cooling of large superconducting magnets

    International Nuclear Information System (INIS)

    Green, M.A.; Burns, W.A.; Taylor, J.D.

    1979-08-01

    A major problem shared by all large superconducting magnets is the cryogenic cooling system. Most large magnets are cooled by some variation of the helium bath. Helium bath cooling becomes more and more troublesome as the size of the magnet grows and as geometric constraints come into play. An alternative approach to cooling large magnet systems is the forced flow, two phase helium system. The advantages of two phase cooling in many magnet systems are shown. The design of a two phase helium system, with its control dewar, is presented. The paper discusses pressure drop of a two phase system, stability of a two phase system and the method of cool down of a two phase system. The results of experimental measurements at LBL are discussed. Included are the results of cool down and operation of superconducting solenoids

  12. Dynamic Simulation of AN Helium Refrigerator

    Science.gov (United States)

    Deschildre, C.; Barraud, A.; Bonnay, P.; Briend, P.; Girard, A.; Poncet, J. M.; Roussel, P.; Sequeira, S. E.

    2008-03-01

    A dynamic simulation of a large scale existing refrigerator has been performed using the software Aspen Hysys®. The model comprises the typical equipments of a cryogenic system: heat exchangers, expanders, helium phase separators and cold compressors. It represents the 400 W @ 1.8 K Test Facility located at CEA—Grenoble. This paper describes the model development and shows the possibilities and limitations of the dynamic module of Aspen Hysys®. Then, comparison between simulation results and experimental data are presented; the simulation of cooldown process was also performed.

  13. Coldness generation and heat revalorization: cryogenic machines; Production de froid et revalorisation de la chaleur: machines cryogeniques

    Energy Technology Data Exchange (ETDEWEB)

    Feidt, M. [Institut National des Sciences Appliquees (INSA), 69 - Villeurbanne (France)

    2005-12-01

    This study treats more particularly of the generation and use of very low temperatures (typically below -100 deg. C). Such temperatures involve different techniques and new physical principles which are examined in this document. The high temperature re-valorization of heat remains poorly explored and is just evoked in this document. Content: 1 - temperature range of cryogenics; 2 - cascade cycles; 3 - gases liquefaction: liquid air, liquid helium, particular properties of helium and refrigeration (Pomaranchuk effect, helium refrigerators); 4 - thermomagnetic effects: basic principles, magnetic refrigerating machine; 5 - conclusions and perspectives about cryogenics. (J.S.)

  14. Mixed helium-3 - helium-4 calorimeter. Very low temperature calorimetry; Calorimetre mixte a helium-3 et helium-4. Calorimetrie a tres basse temperature

    Energy Technology Data Exchange (ETDEWEB)

    Testard, O [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-06-01

    A description is given of a double-racket calorimeter using helium-4 and helium-3 as the cryogenic fluids and making it possible to vary the temperature continuously from 0.35 K to 4.2 K. By using an electric thermal regulator together with liquid hydrogen it is possible to extend this range up to about 30 K. In the second part, a review is made of the various, methods available for measuring specific heats. The method actually used in the apparatus previously described is described in detail. The difficulties arising from the use of an exchange gas for the thermal contact have been solved by the use of adsorption pumps. (author) [French] On decrit un calorimetre a double enceinte utilisant comme fluide cryogenique l'helium-4 et l'helium-3 et permettant de varier continuement la temperature de 0,35 K a 4,2 K. L'utilisation d'un regulateur thermique electrique ainsi que celle d'hydrogene, liquide permettent d'etendre cette gamme jusqu'a 30 K environ. Dans une deuxieme partie, on passe en revue les diverses methodes de mesure des chaleurs specifiques. La methode concrete utilisee dans l'appareil precedemment decrit est exposee en detail. Les difficultes inherentes a l'utilisation de gaz d'echange comme agent de contact thermique ont ete levees par la mise en oeuvre de pompes a adsorbant. (auteur)

  15. Cryogenics for the Large Hadron Collider

    CERN Document Server

    Lebrun, P

    2000-01-01

    The Large Hadron Collider (LHC), a 26.7 km circumference superconducting accelerator equipped with high-field magnets operating in superfluid helium below 1.9 K, has now fully entered construction at CERN, the European Laboratory for Particle Physics. The heart of the LHC cryogenic system is the quasi-isothermal magnet cooling scheme, in which flowing two-phase saturated superfluid helium removes the heat load from the 36000 ton cold mass, immersed in some 400 m/sup 3/ static pressurised superfluid helium. The LHC also makes use of supercritical helium for nonisothermal cooling of the beam screens which intercept most of the dynamic heat loads at higher temperature. Although not used in normal operation, liquid nitrogen will provide the source of refrigeration for precooling the machine. Refrigeration for the LHC is produced in eight large refrigerators, each with an equivalent capacity of about 18 kW at 4.5 K, completed by 1.8 K refrigeration units making use of several stages of hydrodynamic cold compressor...

  16. Coupled Cryogenic Thermal and Electrical Models for Transient Analysis of Superconducting Power Devices with Integrated Cryogenic Systems

    Science.gov (United States)

    Satyanarayana, S.; Indrakanti, S.; Kim, J.; Kim, C.; Pamidi, S.

    2017-12-01

    Benefits of an integrated high temperature superconducting (HTS) power system and the associated cryogenic systems on board an electric ship or aircraft are discussed. A versatile modelling methodology developed to assess the cryogenic thermal behavior of the integrated system with multiple HTS devices and the various potential configurations are introduced. The utility and effectiveness of the developed modelling methodology is demonstrated using a case study involving a hypothetical system including an HTS propulsion motor, an HTS generator and an HTS power cable cooled by an integrated cryogenic helium circulation system. Using the methodology, multiple configurations are studied. The required total cooling power and the ability to maintain each HTS device at the required operating temperatures are considered for each configuration and the trade-offs are discussed for each configuration. Transient analysis of temperature evolution in the cryogenic helium circulation loop in case of a system failure is carried out to arrive at the required critical response time. The analysis was also performed for a similar liquid nitrogen circulation for an isobaric condition and the cooling capacity ratio is used to compare the relative merits of the two cryogens.

  17. On-board cryogenic system for magnetic levitation of trains

    Energy Technology Data Exchange (ETDEWEB)

    Baldus, S A.W.; Kneuer, R; Stephan, A

    1975-02-01

    An experimental car based on electrodynamic levitation with superconducting magnets was developed and manufactured with an on-board cryogenic system. This system has to cope with new conditions and cryogenic tasks. It can be characterized in principle by liquid helium heat exchanger units, compressors, transfer lines, rotable and movable couplings and junctions. All transfer lines and couplings consist of three coaxial ducts for three different streams. Processes and components are discussed, and a brief description of the first results for the whole system under simulation conditions is given.

  18. On-board cryogenic system for magnetic levitation of trains

    International Nuclear Information System (INIS)

    Asztalos, St.; Baldus, W.; Kneuer, R.; Stephan, A.

    1974-01-01

    An experimental car based on electrodynamic levitation with superconducting magnets has been developed and manufactured by AEG, BBC, Siemens and other partners, together with Linde AG as the firm responsible for the on-board cryogenic system. This system has to cope with new conditions and cryogenic tasks. It can be characterized in principle by liquid helium heat exchanger units, compressors, transfer lines, rotatable and movable couplings and junctions. All transfer lines and couplings consist of three coaxial ducts for three different streams. This paper reports on processes and components. A brief description of the first results for the whole system under simulation conditions is given. (author)

  19. Cryogenic System for the Cryomodule Test Stand at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    White, Michael J. [Fermilab; Hansen, Benjamin [Fermilab; Klebaner, Arkadiy [Fermilab

    2017-10-09

    This paper describes the cryogenic system for the Cryomodule Test Stand (CMTS) at the new Cryomodule Test Facility (CMTF) located at Fermilab. CMTS is designed for production testing of the 1.3 GHz and 3.9GHz cryomodules to be used in the Linac Coherent Light Source II (LCLSII), which is an upgrade to an existing accelerator at Stanford Linear Accelerator Laboratory (SLAC). This paper will focus on the cryogenic system that extends from the helium refrigeration plant to the CMTS cave. Topics covered will include component design, installation and commissioning progress, and operational plans. The paper will conclude with a description of the heat load measurement plan.

  20. Introduction to cryogenic engineering

    CERN Multimedia

    CERN. Geneva; Vandoni, Giovanna; Niinikoski, Tapio O

    2005-01-01

    Cryogenic engineering is one of the key technologies at CERN. It is widely used in research and has many applications in industry and last but not least in medicine. In research cryogenic engineering and its applications are omnipresent from the smallest laboratories to fusion reactors, hughe detectors and accelerators. With the termination of the LHC, CERN will in fact become the world's largest cryogenic installation. This series of talks intends to introduce the non-cryogenist to the basic principles and challenges of cryogenic engineering and its applications. The course will also provide a basis for practical application as well as for further learning.

  1. Cryogenics for LDR

    Science.gov (United States)

    Kittel, Peter

    1988-01-01

    Three cryogenic questions of importance to Large Deployable Reflector (LDR) are discussed: the primary cooling requirement, the secondary cooling requirement, and the instrument changeout requirement.

  2. A Low Heat Inleak Cryogenic Station for Testing HTS Current Leads for the Large Hadron Collider

    CERN Document Server

    Ballarino, A; Gomes, P; Métral, L; Serio, L; Suraci, A

    1999-01-01

    The LHC will be equipped with about 8000 superconducting magnets of all types. The total current to be transported into the cryogenic enclosure amounts to some 3360 kA. In order to reduce the heat load into the liquid helium, CERN intends to use High Temperature Superconducting (HTS) material for leads having current ratings up to 13 kA. The resistive part of the leads is cooled by forced flow of gaseous helium between 20 K and 300 K. The HTS part of the lead is immersed in a 4.5 K liquid helium bath, operates in self cooling conditions and is hydraulically separated from the resistive part. A cryogenic test station has been designed and built in order to assess the thermal and electrical performances of 13 kA prototype current leads. We report on the design, commissioning and operation of the cryogenic test station and illustrate its performance by typical test results of HTS current leads.

  3. Dynamic simulations of the cryogenic system of a tokamak

    International Nuclear Information System (INIS)

    Cirillo, R.; Hoa, C.; Michel, F.; Rousset, B.; Poncet, J.M.

    2015-01-01

    In a tokamak plasma confinement is achieved through high magnetic fields generated by superconductive coils that need to be cooled down to 4.4 K with a forced flow of supercritical Helium. Tokamak's coil system works cyclically and so it is subject to pulsed heat loads which have to be handled by the refrigerator. This latter has to be sized on the average power value and not according to the peak to limit investment and operation costs and hence the heat load needs to be smoothed. CEA Grenoble is in charge of providing the cryogenic system for the Japanese tokamak JT60-SA, currently under construction in Naka (Japan). Hence, in order to model and study the smoothing strategies, an experimental set up: HELIOS (Helium Loop for high load smoothing) has been built. This is a scaled down model (1:20) of the helium distribution system whose main components are a saturated helium bath and a supercritical helium loop. This large installation can reproduce conditions of pressure, temperature and transport times, similar to those expected in the cooling circuits of the central solenoid superconducting magnets of JT-60SA. The peak loads representative of the tokamak operation have been reproduced and smoothed before they arrive in the refrigerator, by means of a saturated helium bath (thermal reservoir). A dynamic modelling of the cryogenic system is presented, with results on the pulsed load scenarios. All the simulations have been performed with EcosimPro software developed and the cryogenic library: CRYOLIB. This document is made up of an abstract and the slides of the presentation

  4. New Cryogenic Optical Test Capability at Marshall Space Flight Center's Space Optics Manufacturing Technology Center

    Science.gov (United States)

    Kegley, Jeff; Burdine, Robert V. (Technical Monitor)

    2002-01-01

    A new cryogenic optical testing capability exists at Marshall Space Flight Center's Space Optics Manufacturing Technology Center (SOMTC). SOMTC has been performing optical wavefront testing at cryogenic temperatures since 1999 in the X-ray Cryogenic Test Facility's (XRCF's) large vacuum chamber. Recently the cryogenic optical testing capability has been extended to a smaller vacuum chamber. This smaller horizontal cylindrical vacuum chamber has been outfitted with a helium-cooled liner that can be connected to the facility's helium refrigeration system bringing the existing kilowatt of refrigeration capacity to bear on a 1 meter diameter x 2 meter long test envelope. Cryogenic environments to less than 20 Kelvin are now possible in only a few hours. SOMTC's existing instruments (the Instantaneous Phase-shifting Interferometer (IPI) from ADE Phase-Shift Technologies and the PhaseCam from 4D Vision Technologies) view the optic under test through a 150 mm clear aperture BK-7 window. Since activation and chamber characterization tests in September 2001, the new chamber has been used to perform a cryogenic (less than 30 Kelvin) optical test of a 22.5 cm diameter x 127 cm radius of curvature Si02 mirror, a cryogenic survival (less than 30 Kelvin) test of an adhesive, and a cryogenic cycle (less than 20 Kelvin) test of a ULE mirror. A vibration survey has also been performed on the test chamber. Chamber specifications and performance data, vibration environment data, and limited test results will be presented.

  5. Performance of a proximity cryogenic system for the ATLAS central solenoid magnet

    CERN Document Server

    Doi, Y; Makida, Y; Kondo, Y; Kawai, M; Aoki, K; Haruyama, T; Kondo, T; Mizumaki, S; Wachi, Y; Mine, S; Haug, F; Delruelle, N; Passardi, Giorgio; ten Kate, H H J

    2002-01-01

    The ATLAS central solenoid magnet has been designed and constructed as a collaborative work between KEK and CERN for the ATLAS experiment in the LHC project The solenoid provides an axial magnetic field of 2 Tesla at the center of the tracking volume of the ATLAS detector. The solenoid is installed in a common cryostat of a liquid-argon calorimeter in order to minimize the mass of the cryostat wall. The coil is cooled indirectly by using two-phase helium flow in a pair of serpentine cooling line. The cryogen is supplied by the ATLAS cryogenic plant, which also supplies helium to the Toroid magnet systems. The proximity cryogenic system for the solenoid has two major components: a control dewar and a valve unit In addition, a programmable logic controller, PLC, was prepared for the automatic operation and solenoid test in Japan. This paper describes the design of the proximity cryogenic system and results of the performance test. (7 refs).

  6. The design of the helium refrigerator for TORE SUPRA

    International Nuclear Information System (INIS)

    Gistau, G.M.; Claudet, G.

    1984-01-01

    The special cryogenic requirements of TORE SUPRA have called for novel solutions. Pumping the 1,75 K (13 mb) helium bath is achieved by the use of a pair of centrifugal pumps operating at very low temperature, backed up by liquid rings pumps at room temperature. Four oil-lubricated screw compressors mounted in series-parallel form the main cycle helium compression set. The Joule-Thomson expansion valve is replaced by a mechanical expansion engine working with a bi-phase exhaust. The control of the refrigeration system is entirely automatic

  7. Operating experience using venturi flow meters at liquid helium temperature

    International Nuclear Information System (INIS)

    Wu, K.C.

    1992-01-01

    Experiences using commercial venturi to measure single phase helium flow near 4 K (degree Kelvin) for cooling superconducting magnets have been presented. The mass flow rate was calculated from the differential pressure and the helium density evaluated from measured pressure and temperature. The venturi flow meter, with a full range of 290 g/s (0.29 Kg/s) at design conditions, has been found to be reliable and accurate. The flow measurements have been used, with great success, for evaluating the performance of a cold centrifugal compressor, the thermal acoustic heat load of a cryogenic system and the cooling of a superconducting magnet after quench

  8. Cryogenic system of the prototype of the superconducting magnet for a deuteron cyclotron-1

    International Nuclear Information System (INIS)

    Alenitskij, Yu.G.; Buzdavin, A.P.; Vasilenko, A.T.

    1987-01-01

    The results achieved in developing a cryogenic system for the superconducting magnet of the deuteron cyclotron are described. The cryogenic system consists of a liquefier-refrigerator with the output 40 l.h, or 150 W of power taken off at 4.5 K, a satellite refrigerator, a cryostat of the superconductiong magnet coil and vessels for liquid nitrogen and helium. Now auxiliary equipment is being mounted and the main parts of the magnet are being manufatured

  9. Cryogenic system of steady state superconducting Tokamak SST-1: Operational experience and controls

    International Nuclear Information System (INIS)

    Sarkar, B.; Tank, Jignesh; Panchal, Pradip; Sahu, A.K.; Bhattacharya, Ritendra; Phadke, Gaurang; Gupta, N.C.; Gupta, Girish; Shah, Nitin; Shukla, Pawan; Singh, Manoj; Sonara, Dasarath; Sharma, Rajiv; Saradha, S.; Patel, J.C.; Saxena, Y.C.

    2006-01-01

    The cryogenic system of SST-1 consists of the helium cryogenic system and the nitrogen cryogenic system. The main components of the helium cryogenic system are (a) 1.3 kW helium refrigerator/liquefier (HRL) and (b) warm gas management system (WGM), where as, the nitrogen cryogenic system called as liquid nitrogen (LN 2 ) management system consists of storage tanks and a distribution system. The helium flow distribution and control to different sub-systems is achieved by the integrated flow distribution and control (IFDC) system. The HRL has been commissioned and operated for performing a single toroidal field coil test as well as for the first commissioning of SST-1 superconducting-magnets up to 68 K. Analysis of the results shows that the compressor and turbine parameters of the HRL, namely, the speed and pressure are very stable during operation of the HRL, confirming to the reliability in control of thermo-dynamic parameters of the system. The thermal shield of the SST-1 cryostat consists of ten different types of panels, which have been cooled down to the minimum temperature of 80 K and maintained during the first commissioning of SST-1. The operation and controls of the LN2 management system have been found to be as per the design consideration

  10. Design progress of cryogenic hydrogen system for China Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G. P.; Zhang, Y.; Xiao, J.; He, C. C.; Ding, M. Y.; Wang, Y. Q.; Li, N.; He, K. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P.R. (China)

    2014-01-29

    China Spallation Neutron Source (CSNS) is a large proton accelerator research facility with 100 kW beam power. Construction started in October 2011 and is expected to last 6.5 years. The cryogenic hydrogen circulation is cooled by a helium refrigerator with cooling capacity of 2200 W at 20 K and provides supercritical hydrogen to neutron moderating system. Important progresses of CSNS cryogenic system were concluded as follows. Firstly, process design of cryogenic system has been completed including helium refrigerator, hydrogen loop, gas distribution, and safety interlock. Secondly, an accumulator prototype was designed to mitigate pressure fluctuation caused by dynamic heat load from neutron moderation. Performance test of the accumulator has been carried out at room and liquid nitrogen temperature. Results show the accumulator with welding bellows regulates hydrogen pressure well. Parameters of key equipment have been identified. The contract for the helium refrigerator has been signed. Mechanical design of the hydrogen cold box has been completed, and the hydrogen pump, ortho-para hydrogen convertor, helium-hydrogen heat exchanger, hydrogen heater, and cryogenic valves are in procurement. Finally, Hydrogen safety interlock has been finished as well, including the logic of gas distribution, vacuum, hydrogen leakage and ventilation. Generally, design and construction of CSNS cryogenic system is conducted as expected.

  11. Cryogenics for a vertical test stand facility for testing superconducting radio frequency cavities at RRCAT

    International Nuclear Information System (INIS)

    Gupta, Prabhat Kumar; Kumar, Manoj; Kush, P.K.

    2015-01-01

    Vertical Test Stand (VTS) Facility is located in a newly constructed building of Cryo-Engineering and Cryo-Module Development Division (CCDD). This test facility is one of the important facilities to develop SCRF technologies for superconducting accelerators like Indian Spallation Neutron Source. VTS has to be used for regular testing of the Superconducting Radio Frequency (SRF) Niobium cavities at nominal frequency of 1.3 GHz/ 650 MHz at 4 K / 2 K liquid helium (LHe) bath temperatures. Testing of these cavities at 2 K evaluates cavity processing methods, procedures and would also serve as a pre-qualification test for cavity to test it in horizontal cryostat, called horizontal test stand, with other cavity components such as tuner and helium vessel. Cryogenic technologies play a major role in these cavity testing facilities. Achieving and maintaining a stable temperature of 2 K in these test stands on regular and reliable basis is a challenging task and require broad range of cryogenic expertise, large scale system level understanding and many in-house technological and process developments. Furthermore this test stand will handle large amount of liquid helium. Therefore, an appropriately designed infrastructure is required to handle such large amount of helium gas generated during the operation of VTS .This paper describes the different cryogenic design aspects, initial cryogenic operation results and different cryogenic safety aspects. (author)

  12. MFTF magnet cryogenics

    International Nuclear Information System (INIS)

    VanSant, J.H.

    1981-07-01

    The prime requirement of the cryogenics of the magnets is to assure a superconducting state for the magnet coils, a large task considering their enormous size. The following presentation addresses the principal topics that have been considered in this cryogenic design

  13. Full Cryogenic Test of 600 A HTS Hybrid Current Leads for the LHC

    CERN Document Server

    Al-Mosawi, MK; Beduz, C; Ballarino, A; Yang, Y

    2007-01-01

    For full cryogenic test of CERN 600 A High Temperature Superconducting (HTS) current leads prior to integration into the Large Hadron Collider (LHC), a ded. facility has been designed, constructed and operated at the University of Southampton. The facility consists of purpose-built test cryostats, 20 K helium gas supply, helium gas flow and temperature control systems and quench protection system. Over 400 such leads have already been successfully tested and qualified for installation at CERN. This paper describes various design and operation aspects of the test facility and presents the detailed cryogenic test results of the CERN 600 A current leads, including steady state 20 K flow rates.

  14. Five second helium neutral beam injection using argon-frost cryopumping techniques

    International Nuclear Information System (INIS)

    Phillips, J.C.; Kellman, D.H.; Hong, R.; Kim, J.; Laughon, G.M.

    1995-10-01

    High power helium neutral beams for the heating of tokamak discharges can now be provided for 5 s by using argon cryopumping (of the helium gas) in the beamlines. A system has now been installed to deposit a layer of argon frost on the DIII-D neutral beam cryopanels, between tokamak injection pulses. The layer serves to trap helium on the cryopanels providing sufficient pumping speed for 5 s helium beam extraction. The argon frosting hardware is now present on two of four DIII-D neutral beamlines, allowing injection of up to 6 MW of helium neutral beams per discharge, with pulse lengths of up to 5 s. The argon frosting system is described, along with experimental results demonstrating its effectiveness as a method of economically extending the capabilities of cryogenic pumping panels to allow multi-second helium neutral beam injection

  15. Cryogenic Risk Assessments before Works in the LHC Tunnel

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Tests conducted in 2013/4 demonstrated that a small, residual risk to expose personnel to a helium spill exists in the LHC. Helium spills with a mass flow of less than 100 g s^-1 could be caused by workers accidentally damaging sensitive equipment in the cryogenic distribution system, such as instrumentation feedthroughs. In order to control this risk, a cryogenic risk assessment for all works taking place in the vicinity of such sensitive equipment is mandatory. The risk assessment and its recommendations are approved by the hierarchy and the complex manager before work can start. After introducing the risk assessment procedure, I will give some feedback on its implementation and present status.

  16. Using e-e+→ b bar b to test properties of new interactions at CERN LEP 2 and higher energies

    International Nuclear Information System (INIS)

    Gounaris, G.J.; Papadamou, D.T.; Renard, F.M.

    1997-01-01

    We show that in e - e + colliders at energies above the Z peak, the process e - e + →b bar b becomes very sensitive to the presence of residual new physics (NP) effects described by the dim=6 SU(3)xSU(2)xU(1) gauge invariant operators O qW , O qB , and O bB . This observation should be combined with the already known great sensitivity of the light fermion production through e - e + annihilation above the Z peak to the bosonic operators bar O DW and bar O DB . It is important to emphasize that the effects of all these operators are largely hidden at the Z peak; while they are enhanced beyond it since these operators grow like q 2 , a fact which becomes transparent when using the open-quotes Z-peak subtracted representation.close quotes The observability limits for detecting these operators at CERN LEP 2 and the Next Linear Collider, through such light fermion production processes, are also established. copyright 1997 The American Physical Society

  17. Study of Hydrogen Pumping through Condensed Argon in Cryogenic pump

    International Nuclear Information System (INIS)

    Jadeja, K A; Bhatt, S B

    2012-01-01

    In ultra high vacuum (UHV) range, hydrogen is a dominant residual gas in vacuum chamber. Hydrogen, being light gas, pumping of hydrogen in this vacuum range is limited with widely used UHV pumps, viz. turbo molecular pump and cryogenic pump. Pre condensed argon layers in cryogenic pump create porous structure on the surface of the pump, which traps hydrogen gas at a temperature less than 20° K. Additional argon gas injection in the cryogenic pump, at lowest temperature, generates multiple layers of condensed argon as a porous frost with 10 to 100 A° diameters pores, which increase the pumping capacity of hydrogen gas. This pumping mechanism of hydrogen is more effective, to pump more hydrogen gas in UHV range applicable in accelerator, space simulation etc. and where hydrogen is used as fuel gas like tokamak. For this experiment, the cryogenic pump with a closed loop refrigerator using helium gas is used to produce the minimum cryogenic temperature as ∼ 14° K. In this paper, effect of cryosorption of hydrogen is presented with different levels of argon gas and hydrogen gas in cryogenic pump chamber.

  18. Series Supply of Cryogenic Venturi Flowmeters for the ITER Project

    International Nuclear Information System (INIS)

    André, J; Poncet, J M; Ercolani, E; Clayton, N; Journeaux, J Y

    2015-01-01

    In the framework of the ITER project, the CEA-SBT has been contracted to supply 277 venturi tube flowmeters to measure the distribution of helium in the superconducting magnets of the ITER tokamak. Six sizes of venturi tube have been designed so as to span a measurable helium flowrate range from 0.1 g/s to 400g/s. They operate, in nominal conditions, either at 4K or at 300K, and in a nuclear and magnetic environment. Due to the cryogenic conditions and the large number of venturi tubes to be supplied, an individual calibration of each venturi tube would be too expensive and time consuming. Studies have been performed to produce a design which will offer high repeatability in manufacture, reduce the geometrical uncertainties and improve the final helium flowrate measurement accuracy. On the instrumentation side, technologies for differential and absolute pressure transducers able to operate in applied magnetic fields need to be identified and validated. The complete helium mass flow measurement chain will be qualified in four test benches: - A helium loop at room temperature to insure the qualification of a statistically relevant number of venturi tubes operating at 300K.- A supercritical helium loop for the qualification of venturi tubes operating at cryogenic temperature (a modification to the HELIOS test bench). - A dedicated vacuum vessel to check the helium leak tightness of all the venturi tubes. - A magnetic test bench to qualify different technologies of pressure transducer in applied magnetic fields up to 100mT. (paper)

  19. Compact cryogenic attachment for Moessbauer spectroscopy with microwave excitation

    International Nuclear Information System (INIS)

    Didenko, N.P.; Amelin, G.P.; Zelentsov, V.I.; Kaminskii, V.L.; Fedorov, N.P.; Fal'kovich, V.M.

    1989-01-01

    A compact cryogenic attachment is described that is placed on a standard helium Dewar flask and permits recording of Moessbauer spectra with excitation by millimeter-band radiation in the temperature range of 4.3-300 K. The design of the attachment allows operation with various gamma-radiation detectors in both horizontal and vertical Moessbauer measurement geometries and its placement in superconducting magnets with a large warm zone

  20. Large Cryogenic Infrastructure for LHC Superconducting Magnet and Cryogenic Component Tests: Layout, Commissioning and Operational Experience

    International Nuclear Information System (INIS)

    Calzas, C.; Chanat, D.; Knoops, S.; Sanmarti, M.; Serio, L.

    2004-01-01

    The largest cryogenic test facility at CERN, located at Zone 18, is used to validate and to test all main components working at cryogenic temperature in the LHC (Large Hadron Collider) before final installation in the machine tunnel. In total about 1300 main dipoles, 400 main quadrupoles, 5 RF-modules, eight 1.8 K refrigeration units will be tested in the coming years.The test facility has been improved and upgraded over the last few years and the first 18 kW refrigerator for the LHC machine has been added to boost the cryogenic capacity for the area via a 25,000 liter liquid helium dewar. The existing 6 kW refrigerator, used for the LHC Test String experiments, will also be employed to commission LHC cryogenic components.We report on the design and layout of the test facility as well as the commissioning and the first 10,000 hours operational experience of the test facility and the 18 kW LHC refrigerator

  1. Some of the QRL team in UJ22 of the LHC tunnel, where the last sector of the cryogenic distribution line was installed.

    CERN Multimedia

    Viviane Li

    2006-01-01

    The cryogenic distribution line "the QRL" is a circle built in 8 sectors, each approximately 3 km in length. It will circulate helium in liquid and gas phases, at different temperatures and pressures, to provide the cryogenic conditions for the superconducting magnets in the LHC tunnel.

  2. Cryogenic techniques for large superconducting magnets in space

    International Nuclear Information System (INIS)

    Green, M.A.

    1988-12-01

    A large superconducting magnet is proposed for use in a particle astrophysics experiment, ASTROMAG, which is to be mounted on the United States Space Station. This experiment will have a two-coil superconducting magnet with coils which are 1.3 to 1.7 meters in diameter. The two-coil magnet will have zero net magnetic dipole moment. The field 15 meters from the magnet will approach earth's field in low earth orbit. The issue of high Tc superconductor will be discussed in the paper. The reasons for using conventional niobium-titanium superconductor cooled with superfluid helium will be presented. Since the purpose of the magnet is to do particle astrophysics, the superconducting coils must be located close to the charged particle detectors. The trade off between the particle physics possible and the cryogenic insulation around the coils is discussed. As a result, the ASTROMAG magnet coils will be operated outside of the superfluid helium storage tank. The fountain effect pumping system which will be used to cool the coil is described in the report. Two methods for extending the operating life of the superfluid helium dewar are discussed. These include: operation with a third shield cooled to 90 K with a sterling cycle cryocooler, and a hybrid cryogenic system where there are three hydrogen-cooled shields and cryostat support heat intercept points. Both of these methods will extend the ASTROMAG cryogenic operating life from 2 years to almost 4 years. 14 refs., 8 figs., 4 tabs

  3. A vibrating quartz fork - a tool for cryogenic helium research

    Czech Academy of Sciences Publication Activity Database

    Blažková, Michaela; Člověčko, M.; Eltsov, V. B.; Gažo, E.; de Graaf, R.; Hosio, J.J.; Krusius, M.; Schmoranzer, D.; Schoepe, W.; Skrbek, Ladislav; Skyba, P.; Solntsev, R.E.; Vinen, W. F.

    2008-01-01

    Roč. 150, - (2008), s. 525-535 ISSN 0022-2291 R&D Projects: GA ČR GA202/05/0218 Grant - others:GAUK(CZ) 7953/2007; Transnational Access Programme(XE) RITA -CT-2003-505313 Institutional research plan: CEZ:AV0Z10100520 Keywords : normal 3He * superfluid 3He * superfluid 4He * turbulence, * cavitation * quartz tuning fork Subject RIV: BK - Fluid Dynamics Impact factor: 1.034, year: 2008

  4. Anomalous heat transport and condensation in convection of cryogenic helium

    Czech Academy of Sciences Publication Activity Database

    Urban, Pavel; Schmoranzer, D.; Hanzelka, Pavel; Sreenivasan, K. R.; Skrbek, L.

    2013-01-01

    Roč. 110, č. 20 (2013), s. 8036-8039 ISSN 0027-8424 R&D Projects: GA ČR GPP203/12/P897 Institutional support: RVO:68081731 Keywords : two-phase convection * temperature inversion * condensation * rain formation Subject RIV: BK - Fluid Dynamics Impact factor: 9.809, year: 2013

  5. Temperature Stratification in a Cryogenic Fuel Tank

    Science.gov (United States)

    Daigle, Matthew John; Smelyanskiy, Vadim; Boschee, Jacob; Foygel, Michael Gregory

    2013-01-01

    A reduced dynamical model describing temperature stratification effects driven by natural convection in a liquid hydrogen cryogenic fuel tank has been developed. It accounts for cryogenic propellant loading, storage, and unloading in the conditions of normal, increased, and micro- gravity. The model involves multiple horizontal control volumes in both liquid and ullage spaces. Temperature and velocity boundary layers at the tank walls are taken into account by using correlation relations. Heat exchange involving the tank wall is considered by means of the lumped-parameter method. By employing basic conservation laws, the model takes into consideration the major multi-phase mass and energy exchange processes involved, such as condensation-evaporation of the hydrogen, as well as flows of hydrogen liquid and vapor in the presence of pressurizing helium gas. The model involves a liquid hydrogen feed line and a tank ullage vent valve for pressure control. The temperature stratification effects are investigated, including in the presence of vent valve oscillations. A simulation of temperature stratification effects in a generic cryogenic tank has been implemented in Matlab and results are presented for various tank conditions.

  6. Properties of strain gages at cryogenic temperature

    International Nuclear Information System (INIS)

    Shibata, Nobuo; Fujiyoshi, Toshimitsu.

    1978-01-01

    At the time of developing superconduction generators, the stress measurement for rotor parts is required to grasp the safety and performance of the rotor at cryogenic temperature, which is cooled with liquid helium. In case of carrying out the stress measurement with strain gages, the problems are as follows. The strain gages and lead wires are exposed to cryogenic temperature from 4 to 10 K and strong magnetic field of about 3T, and subjected to high centrifugal acceleration of about 500G. In order to establish the techniques of the stress measurement under such conditions, the adhesives and damp-proof coatings for strain gages and strain gages themselves in Japan and foreign countries were examined on the properties at cryogenic temperature. As for the properties of strain gages, mainly the apparent strain owing to temperature change was investigated, and the change of the gage factors was studies only at liquid nitrogen temperature. The stress measurement with strain gages at low temperature had been studied in detail down to liquid nitrogen temperature concerning LNG tanks. The experimental apparatus, the samples, the testing methods and the test results of cooling tests on adhesives and damp-proof coatings, and the temperature characteristics of strain gages are reported. The usable adhesives and coatings were found, and correction by accurate temperature measurement is required for apparent strain. (Kako, I.)

  7. Advanced monitoring, fault diagnostics, and maintenance of cryogenic systems

    CERN Document Server

    Girone, Mario; Pezzetti, Marco

    In this Thesis, advanced methods and techniques of monitoring, fault diagnostics, and predictive maintenance for cryogenic processes and systems are described. In particular, in Chapter 1, mainstreams in research on measurement systems for cryogenic processes are reviewed with the aim of dening key current trends and possible future evolutions. Then, in Chapter 2, several innovative methods are proposed. A transducer based on a virtual ow meter is presented for monitoring helium distribution and consumption in cryogenic systems for particle accelerators [1]. Furthermore, a comprehensive metrological analysis of the proposed transducer for verifying the metrological performance and pointing out most critical uncertainty sources is described [2]. A model-based method for fault detection and early-stage isolation, able to work with few records of Frequency Response Function (FRF) on an unfaulty compressor, is then proposed [3]. To enrich the proposal, a distributed diagnostic procedure, based on a micro-genetic...

  8. Analysis for liquid cryogen spillage in the superconducting cyclotron building at VECC

    CERN Document Server

    Roy S ,; Pal, G; Bhandari, R K

    2009-01-01

    The cryogenic system uses liquid helium and liquid nitrogen to cool the superconducting cyclotron magnet and its cryopanels. In order to assess safety scenarios subsequent to an unusual leakage of cryogens from the system, a deterministic analysis has been carried out to estimate the variation of oxygen concentration with time at several locations of superconducting cyclotron building. The entire process is simulated assuming evaporated cryogens mixes instantaneously with air in the confined space, the ventilation system of the cyclotron building is operational, fresh air continuously enters the confined volume and mixes instantaneously with air in the confined space.

  9. Helium the disappearing element

    CERN Document Server

    Sears, Wheeler M

    2015-01-01

    The subject of the book is helium, the element, and its use in myriad applications including MRI machines, particle accelerators, space telescopes, and of course balloons and blimps. It was at the birth of our Universe, or the Big Bang, where the majority of cosmic helium was created; and stellar helium production continues. Although helium is the second most abundant element in the Universe, it is actually quite rare here on Earth and only exists because of radioactive elements deep within the Earth. This book includes a detailed history of the discovery of helium, of the commercial industry built around it, how the helium we actually encounter is produced within the Earth, and the state of the helium industry today. The gas that most people associate with birthday party balloons is running out. “Who cares?” you might ask. Well, without helium, MRI machines could not function, rockets could not go into space, particle accelerators such as those used by CERN could not operate, fiber optic cables would not...

  10. Helium dilution refrigerator

    International Nuclear Information System (INIS)

    1973-01-01

    A new system of continuous heat exchange for a helium dilution refrigerator is proposed. The 3 He effluent tube is concurrent with the affluent mixed helium tube in a vertical downward direction. Heat exchange efficiency is enhanced by placing in series a number of elements with an enlarged surface area

  11. Helium localisation in tritides

    International Nuclear Information System (INIS)

    Flament, J.L.; Lozes, G.

    1982-06-01

    Study of titanium and LaNi 5 type alloys tritides lattice parameters evolution revealed that helium created by tritium decay remains in interstitial sites up to a limit material dependant concentration. Beyond this one exceeding helium precipites in voids [fr

  12. Integrated cryogenic sensors

    International Nuclear Information System (INIS)

    Juanarena, D.B.; Rao, M.G.

    1991-01-01

    Integrated cryogenic pressure-temperature, level-temperature, and flow-temperature sensors have several advantages over the conventional single parameter sensors. Such integrated sensors were not available until recently. Pressure Systems, Inc. (PSI) of Hampton, Virginia, has introduced precalibrated precision cryogenic pressure sensors at the Los Angeles Cryogenic Engineering Conference in 1989. Recently, PSI has successfully completed the development of integrated pressure-temperature and level-temperature sensors for use in the temperature range 1.5-375K. In this paper, performance characteristics of these integrated sensors are presented. Further, the effects of irradiation and magnetic fields on these integrated sensors are also reviewed

  13. Fundamentals of cryogenic engineering

    CERN Document Server

    Mukhopadhyay, Mamata

    2014-01-01

    The author, with her vast and varied experience in teaching and allied fields, clearly enunciates the behaviour and various properties of common cryogenic fluids, methods of liquefaction, and separation and applications of cryogens with thermodynamic analysis for process selection. This profusely illustrated study with clear-cut diagrams and process charts, should serve not only as a textbook for students but also as an excellent reference for researchers and practising engineers on design of cryogenic refrigeration, and liquefaction and separation process plants for various applications.

  14. Polymers at cryogenic temperatures

    CERN Document Server

    Fu, Shao-Yun

    2013-01-01

    Kalia and Fu's novel monograph covers cryogenic treatment, properties and applications of cryo-treated polymer materials. Written by numerous international experts, the twelve chapters in this book offer the reader a comprehensive picture of the latest findings and developments, as well as an outlook on the field. Cryogenic technology has seen remarkable progress in the past few years and especially cryogenic properties of polymers are attracting attention through new breakthroughs in space, superconducting, magnetic and electronic techniques. This book is a valuable resource for researchers, educators, engineers and graduate students in the field and at technical institutions.

  15. FRIB Cryogenic Plant Status

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Kelly D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Ganni, Venkatarao [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Knudsen, Peter N. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Casagranda, Fabio [Michigan State Univ., East Lansing, MI (United States)

    2015-12-01

    After practical changes were approved to the initial conceptual design of the cryogenic system for MSU FRIB and an agreement was made with JLab in 2012 to lead the design effort of the cryogenic plant, many activities are in place leading toward a cool-down of the linacs prior to 2018. This is mostly due to using similar equipment used at CHLII for the 12 GeV upgrade at JLab and an aggressive schedule maintained by the MSU Conventional Facilities department. Reported here is an updated status of the cryogenic plant, including the equipment procurement status, plant layout, facility equipment and project schedule.

  16. Cryogenics theory, processes and applications

    CERN Document Server

    Hayes, Allyson E

    2011-01-01

    Cryogenics is the study of the production of very low temperature (below -150 -C, -238 -F or 123 K) and the behaviour of materials at those temperatures. This book presents current research from across the globe in the study of cryogenics, including the effect of cryogenic treatment on microstructure and mechanical properties of light weight alloys; the application of Fiber Bragg grating sensors at cryogenic temperatures; cryogenic grinding; liquid oxygen magnetohydrodynamics; and, genetic engineering techniques used to improve tolerance to cryopreservation.

  17. A Cryogenic Test Set-Up for the Qualification of Pre-Series Test Cells for the LHC Cryogenic Distribution Line

    CERN Document Server

    Livran, J; Parente, C; Riddone, G; Rybkowski, D; Veillet, N

    2000-01-01

    Three pre-series Test Cells of the LHC Cryogenic Distribution Line (QRL) [1], manufactured by three European industrial companies, will be tested in the year 2000 to qualify the design chosen and verify the thermal and mechanical performances. A dedicated test stand (170 m x 13 m) has been built for extensive testing and performance assessment of the pre-series units in parallel. They will be fed with saturated liquid helium at 4.2 K supplied by a mobile helium dewar. In addition, LN2 cooled helium will be used for cool-down and thermal shielding. For each of the three pre-series units, a set of end boxes has been designed and manufactured at CERN. This paper presents the layout of the cryogenic system for the pre-series units, the calorimetric methods as well as the results of the thermal calculation of the end box test.

  18. Tables of thermodynamic properties of helium magnet coolant

    International Nuclear Information System (INIS)

    McAshan, M.

    1992-07-01

    The most complete treatment of the thermodynamic properties of helium at the present time is the monograph by McCarty: ''Thermodynamic Properties of Helium 4 from 2 to 1500 K at Pressures to 10 8 Pa'', Robert D. McCarty, Journal of Physical and Chemical Reference Data, Vol. 2, page 923--1040 (1973). In this work the complete range of data on helium is examined and the P-V-T surface is described by an equation of state consisting of three functions P(r,T) covering different regions together with rules for making the transition from one region to another. From this thermodynamic compilation together with correlations of the transport properties of helium was published the well-known NBS Technical Note: ''Thermophysical Properties of Helium 4 from 2 to 1500 K with pressures to 1000 Atmospheres'', Robert D. McCarty, US Department of Commerce, National Bureau of Standards Technical Note 631 (1972). This is the standard reference for helium cryogenics. The NBS 631 tables cover a wide range of temperature and pressure, and as a consequence, the number of points tabulated in the region of the single phase coolant for the SSC magnets are relatively few. The present work sets out to cover the range of interest in more detail in a way that is consistent with NBS 631. This new table is essentially identical to the older one and can be used as an auxiliary to it

  19. A Cryogenic High-Reynolds Turbulence Experiment at CERN

    CERN Document Server

    Bézaguet, Alain-Arthur; Knoops, S; Lebrun, P; Pezzetti, M; Pirotte, O; Bret, J L; Chabaud, B; Garde, G; Guttin, C; Hébral, B; Pietropinto, S; Roche, P; Barbier-Neyret, J P; Baudet, C; Gagne, Y; Poulain, C; Castaing, B; Ladam, Y; Vittoz, F

    2002-01-01

    The potential of cryogenic helium flows for studying high-Reynolds number turbulence in the laboratory has been recognised for a long time and implemented in several small-scale hydrodynamic experiments. With its large superconducting particle accelerators and detector magnets, CERN, the European Laboratory for Particle Physics, has become a major world center in helium cryogenics, with several large helium refrigerators having capacities up to 18 kW @ 4.5 K. Combining a small fraction of these resources with the expertise of three laboratories at the forefront of turbulence research, has led to the design, swift implementation, and successful operation of GReC (Grands Reynolds Cryogéniques) a large axisymmetric turbulent-jet experiment. With flow-rates up to 260 g/s of gaseous helium at ~ 5 K and atmospheric pressure, Reynolds numbers up to 107 have been achieved in a 4.6 m high, 1.4 m diameter cryostat. This paper presents the results of the first runs and describes the experimental set-up comprehensively ...

  20. Cryogenic infrastructure at BESSY II. Inventory and outlook

    International Nuclear Information System (INIS)

    Heling, Svenja; Anders, Wolfgang; Heinrich, Jochen; Hellwig, Axel; Janke, Karsten; Molder, Benjamin; Rotterdam, Stefan

    2017-01-01

    The Helmholtz Centre Berlin operates the BESSY II electron storage ring at the Adlershof site. A helium condenser is installed to supply the superconducting wavelength shifter installed in the storage ring with liquid helium. Another liquefier, including a comprehensive cryogenic infrastructure, supplies helium at 1.8 K to several test stands, especially for superconducting cavity resonators. In addition to the operation of the existing plants, a new type of accelerator is currently being set up as part of the bERLinPro project. In order to ensure the required supply of liquid helium, one of the existing helium condensers will be relocated and the plant will be extended by a 10,000 l dewar, three valve boxes, a cold compressor box, a warm pumping station and an 80 K helium system. In addition, the future project BESSY VSR, a further development of the BESSY II storage ring, will see the procurement of a third refrigeration system. A challenge here will be the year-round continuous operation. This paper explains the structure of the plants described above in more detail and provides an insight into the challenges of plant design. Finally, the planned future expansions will be outlined. [de

  1. Cryogenics for LHC experiments

    CERN Multimedia

    2001-01-01

    Cryogenic systems will be used by LHC experiments to maximize their performance. Institutes around the world are collaborating with CERN in the construction of these very low temperature systems. The cryogenic test facility in hall 180 for ATLAS magnets. High Energy Physics experiments have frequently adopted cryogenic versions of their apparatus to achieve optimal performance, and those for the LHC will be no exception. The two largest experiments for CERN's new flagship accelerator, ATLAS and CMS, will both use large superconducting magnets operated at 4.5 Kelvin - almost 270 degrees below the freezing point of water. ATLAS also includes calorimeters filled with liquid argon at 87 Kelvin. For the magnets, the choice of a cryogenic version was dictated by a combination economy and transparency to emerging particles. For the calorimeters, liquid argon was selected as the fluid best suited to the experiment's physics requirements. High Energy Physics experiments are the result of worldwide collaborations and...

  2. Advances in Cryogenic Principles

    Science.gov (United States)

    Barron, R. F.

    During the past 50 years, the use of digital computers has significantly influenced the design and analysis of cryogenic systems. At the time when the first Cryogenic Engineering Conference was held, thermodynamic data were presented in graphical or tabular form (the "steam table" format), whereas thermodynamic data for cryogenic system design is computer generated today. The thermal analysis of cryogenic systems in the 1950s involved analytical solutions, graphical solutions, and relatively simple finite-difference approaches. These approaches have been supplanted by finite-element numerical programs which readily solve complicated thermal problems that could not be solved easily using the methods of the 1950s. In distillation column design, the use of the McCabe-Thiele graphical method for determination of the number of theoretical plates has been replaced by numerical methods that allow consideration of several different components in the feed and product streams.

  3. Installation and Commissioning of the Helium Refrigeration System for the HANARO-CNS

    International Nuclear Information System (INIS)

    Choi, Jung Woon; Kim, Young Ki; Wu, Sang Ik; Son, Woo Jung

    2009-11-01

    The cold neutron source (CNS), which will be installed in the vertical CN hole of the reflector tank at HANARO, makes thermal neutrons to moderate into the cold neutrons with the ranges of 0.1 ∼ 10 meV passing through a moderator at about 22K. A moderator to produce cold neutrons is liquid hydrogen, which liquefies by the heat transfer with cryogenic helium flowing from the helium refrigeration system. For the maintenance of liquid hydrogen in the IPA, the CNS system is mainly consisted of the hydrogen system to supply the hydrogen to the IPA, the vacuum system to keep the cryogenic liquid hydrogen in the IPA, and the helium refrigeration system to liquefy the hydrogen gas. The helium refrigeration system can be divided into two sections: one is the helium compression part from the low pressure gas to the high pressure gas and the other is the helium expansion part from the high temperature gas and pressure to low temperature and pressure gas by the expansion turbine. The helium refrigeration system except the warm helium pipe and the helium buffer tank has been manufactured by Linde Kryotechnik, AG in Switzerland and installed in the research reactor hall, HANARO. Other components have been manufactured in the domestic company. This technical report deals with the issues, its solutions, and other particular points while the helium refrigeration system was installed at site, verified its performance, and conducted its commissioning along the reactor operation. Furthermore, the operation procedure of the helium refrigeration system is included in here for the normal operation of the CNS

  4. Upgrade of the Cryogenic CERN RF Test Facility

    CERN Document Server

    Pirotte, O; Brunner, O; Inglese, V; Koettig, T; Maesen, P; Vullierme, B

    2014-01-01

    With the large number of superconducting radiofrequency (RF) cryomodules to be tested for the former LEP and the present LHC accelerator a RF test facility was erected early in the 1990’s in the largest cryogenic test facility at CERN located at Point 18. This facility consisted of four vertical test stands for single cavities and originally one and then two horizontal test benches for RF cryomodules operating at 4.5 K in saturated helium. CERN is presently working on the upgrade of its accelerator infrastructure, which requires new superconducting cavities operating below 2 K in saturated superfluid helium. Consequently, the RF test facility has been renewed in order to allow efficient cavity and cryomodule tests in superfluid helium and to improve its thermal performances. The new RF test facility is described and its performances are presented.

  5. Upgrade of the cryogenic CERN RF test facility

    International Nuclear Information System (INIS)

    Pirotte, O.; Benda, V.; Brunner, O.; Inglese, V.; Maesen, P.; Vullierme, B.; Koettig, T.

    2014-01-01

    With the large number of superconducting radiofrequency (RF) cryomodules to be tested for the former LEP and the present LHC accelerator a RF test facility was erected early in the 1990’s in the largest cryogenic test facility at CERN located at Point 18. This facility consisted of four vertical test stands for single cavities and originally one and then two horizontal test benches for RF cryomodules operating at 4.5 K in saturated helium. CERN is presently working on the upgrade of its accelerator infrastructure, which requires new superconducting cavities operating below 2 K in saturated superfluid helium. Consequently, the RF test facility has been renewed in order to allow efficient cavity and cryomodule tests in superfluid helium and to improve its thermal performances. The new RF test facility is described and its performances are presented

  6. Development of a Mass Flowmeter based on the Coriolis Acceleration for Liquid, Supercritical and Superfluid Helium

    CERN Document Server

    De Jonge, T; Rivetti, A; Serio, L

    2002-01-01

    Beginning in the 1980's, Coriolis meters have gained generalised acceptance in liquid applications with a worldwide installed base of over 300,000 units. To meet the demands of cryogenic applications below 20 K, off-the-shelf Coriolis meters have been used, with minor design modifications and operational changes. The meters were originally calibrated on water and tested on liquid helium at 4.5 K, supercritical helium around 5 K and superfluid helium below 2 K. The meters maintain their intrinsic robustness and accuracy of better than 1% of measured value; accuracy is independent of density and temperature.

  7. A cryogenic pump with a long continuous run without filling intended for a particle accelerator

    International Nuclear Information System (INIS)

    Bottiglioni, F.; Coutant, J.; Fois, M.; Duthil, R.; Gelebart, J.C.; Lottin, J.C.

    1977-06-01

    A cryogenic pump is described, specially designed to be used in an electrostatic particle accelerator. The same tubular liquid helium bath provides pumping in the accelerating tube and around the beam. The temperature of the bath can be adjusted between 2.2 and 4.2 deg K, the liquid helium level, in the low pressure bath, is keeped constant through a feeding system made of an heat exchanger and an expansion valve. An auxiliary container for liquid nitrogen and liquid helium, at atmospheric pressure, allows a several days continuous run without filling. This system allows refilling of the container without changing the pressure on the bath [fr

  8. Niobium LEP 2 accelerating cavities

    CERN Multimedia

    An accelerating cavity from LEP. This could be cut open to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities were used in an upgrade of the LEP accelerator to double the energy of the particle beams.

  9. Anomalous couplings at LEP2

    International Nuclear Information System (INIS)

    Fayolle, D.

    2002-01-01

    In its second phase, LEP has allowed to study four fermion processes never observed before. Results are presented on the charged triple gauge boson couplings (TGC) from the W-pair, Single W and Single γ production. The anomalous quartic gauge couplings (QGC) are constrained using production of WWγ, νν-barγγ and Z γγ final states. Finally, limits on the neutral anomalous gauge couplings (NGC) using the Z γ and ZZ production processes are also reported. All results are consistent with the Standard Model expectations. (authors)

  10. Colour reconnection at LEP2

    CERN Document Server

    Abreu, P

    2002-01-01

    The preliminary results on the search of colour reconnection effects (CR) from the four experiments at LEP, ALEPH, DELPHI, L3 and OPAL, are reviewed. Extreme models are excluded by studies of standard variables, and on going studies of a method first suggested by L3, the particle flow method (D. Duchesneau, (2001)), are yet inconclusive. (22 refs).

  11. A liquid helium saver

    International Nuclear Information System (INIS)

    Avenel, O.; Der Nigohossian, G.; Roubeau, P.

    1976-01-01

    A cryostat equipped with a 'liquid helium saver' is described. A mass flow rate M of helium gas at high pressure is injected in a counter-flow heat exchanger extending from room to liquid helium temperature. After isenthalpic expansion through a calibrated flow impedance this helium gas returns via the low pressure side of the heat exchanger. The helium boil-off of the cryostat represents a mass flow rate m, which provides additional precooling of the incoming helium gas. Two operating regimes appear possible giving nearly the same efficiency: (1) high pressure (20 to 25 atm) and minimum flow (M . L/W approximately = 1.5) which would be used in an open circuit with helium taken from a high pressure cylinder; and (2) low pressure (approximately = 3 atm), high flow (M . L/W > 10) which would be used in a closed circuit with a rubber diaphragm pumping-compressing unit; both provide a minimum theoretical boil-off factor of about 8%. Experimental results are reported. (U.K.)

  12. Ricor's anniversary of 50 innovative years in cryogenic technology

    Science.gov (United States)

    Filis, Avishai; Segal, Victor; Pundak, Nachman; Bar Haim, Zvi; Danziger, Menachem

    2017-05-01

    Ricor cryogenics was founded in 1967 and since then it has focused on innovative technologies in the cryogenic field. The paper reviews the initial research and development efforts invested in various technologies that have yielded products such as Cryostats for Mossbauer Effect measurement, Liquid gas Dewar containers, Liquid helium vacuum transfer tubes, Cryosurgery and other innovative products. The major registered patents that matured to products such as a magnetic vacuum valve operator, pumped out safety valve and other innovations are reviewed here. As a result of continuous R and D investment, over the years a new generation of innovative Stirling cryogenic products has developed. This development began with massive split slip-on coolers and has progressed as far as miniature IDDCA coolers mainly for IR applications. The accumulated experience in Stirling technology is used also as a platform for developing self-contained water vapor pumps known as MicroStar and NanoStar. These products are also used in collaboration with a research institute in the field of High Temperature Superconductors. The continuous growth in the cryogenic products range and the need to meet market demands have motivated the expansion, of Ricor's manufacturing facility enabling it to become a world leader in the cryocooler field. To date Ricor has manufactured more than 120,000 cryocoolers. The actual cryogenic development efforts and challenges are also reviewed, mainly in the field of long life cryocoolers, ruggedized products, miniaturization and products for space applications.

  13. A word from the DG: A cryogenic success

    CERN Multimedia

    2007-01-01

    The beginning of this month saw the start of a new phase in the LHC project, with its first inauguration, for the LHC cryogenics. This was marked with a symposium in the Globe attended by 178 representatives of the industrial partners and research institutes involved. It also coincided with stable low-temperature operation of the cryogenic plant for sector 7-8, the first sector of the LHC to be cooled down. A look at the LHC web site (http://lhc.web.cern.ch/lhc/) shows this steady operation. The cryogenic system for the LHC is the largest and most complex ever built, involving many large devices on an industrial scale, where reliability is of paramount importance. The LHC’s energy of 7 TeV required a high magnetic field provided by niobium-titanium coils operating at 1.9 K. This is a new temperature regime for large-scale cryogenics, chosen to make use of the excellent heat-transfer properties of helium in its superfluid state. The final design for the LHC cryogenics had to incorporate both newly ordered ...

  14. First operation of the XFEL linac with the 2 K cryogenic system

    Science.gov (United States)

    Paetzold, T.; Petersen, B.; Schnautz, T.; Ueresin, C.; Zajac, J.

    2017-12-01

    The RF operation of the about 800 superconducting 1.3 GHz 9-cell cavities of the XFEL linac requires helium II bath cooling at 2 K, corresponding to a vapor pressure of 3100 Pa. After the first cool-down of the XFEL linac to 4 K in December, 27th 2016 the operation of the 2 K cryogenic system was started in January, 2nd 2017. The 2 K cryogenic system consist of a 4-stage set of cold compressors to compress helium vapor at a mass flow of up to 100 g/s from 2400 Pa to about 110 kPa and a full flow bypass with an arrangement of heat exchangers and control valves. This paper describes the XFEL refrigerating plant, especially the 2 K cryogenic system, the tuning of the cold compressor regulation to adapt to the XFEL linac static and dynamic heat loads and experience of about 6 months of operation.

  15. Design, Construction, Installation and First Commissioning Results of the LHC Cryogenic System

    CERN Document Server

    Claudet, S

    2006-01-01

    The cryogenic system of the Large Hadron Collider (LHC) will be, upon its completion in 2006, the largest in the world in terms of refrigeration capacity with an equivalent to 144 kW at 4.5 K, about 400'000 litres of superfluid helium with 25 km of superconducting magnets below 2 K leading to a cryogen inventory of 100 tons of helium. The challenges involved in the design, construction and installation, as well as the first commissioning results will be addressed in this talk. Particular mention will be made of the problems encountered and how they were or are being solved. Perspectives for LHC will be presented. General considerations for future large cryogenic systems will be briefly proposed.

  16. Operational and troubleshooting experiences in the SST-1 cryogenic system

    Science.gov (United States)

    Mahesuria, G.; Panchal, P.; Panchal, R.; Patel, R.; Sonara, D.; Gupta, N. C.; Srikanth, G. L. N.; Christian, D.; Garg, A.; Bairagi, N.; Patel, K.; Shah, P.; Nimavat, H.; Sharma, R.; Patel, J. C.; Tank, J.; Tanna, V. L.; Pradhan, S.

    2014-01-01

    Recently, the cooldown and current charging campaign have been carried out towards the demonstration of the first successful plasma discharge in the steady state superconducting Tokomak (SST-1). The SST-1 machine consists of cable-in-conduit wound superconducting toroidal as well as poloidal coils, cooled using 1.3 kW at 4.5 K helium refrigerator -cum- liquefier (HRL) system. The cryo system provides the two-phase helium at 0.13 MPa at 4.5 K as well as forced-flow pressurized helium at 0.4 MPa and in addition to 7 g-s-1 liquefaction capacity required for the current leads and other cold mass at 4.5 K. The entire integrated cold masses having different thermo hydraulic resistances cooled with the SST-1 HRL in optimised process parameters. In order to maintain different levels of temperatures and to facilitate smooth and reliable cooldown, warm-up, normal operations as well as to handle abnormal events such as, quench or utilities failures etc., exergy efficient process are adopted for the helium refrigerator-cum-liquefier (HRL) with an installed equivalent capacity of 1.3 kW at 4.5 K. Using the HRL, the cold mass of about 40 tons is being routinely cooled down from ambient temperature to 4.5 K with an average cooldown rate of 0.75 - 1 K-h-1. Long-term cryogenic stable conditions were obtained within 15 days in the superconducting coils and their connecting feeders. Afterwards, all of the cold mass is warmed-up in a controlled manner to ambient temperature. In this paper, we report the recent operational results of the cryogenic system during the first plasma discharge in SST-1 as well as the troubleshooting experiences of the cryogenic plant related hardware.

  17. Gas gap heat switch for a cryogen-free magnet system

    International Nuclear Information System (INIS)

    Barreto, J; De Sousa, P Borges; Martins, D; Bonfait, G; Catarino, I; Kar, S

    2015-01-01

    Cryogen-free superconducting magnet systems (CFMS) have become popular over the last two decades for the simple reason that the use of liquid helium is rather cumbersome and that helium is a scarce resource. Some available CFMS use a mechanical cryocooler as the magnet's cold source. However, the variable temperature insert (VTI) for some existing CFMS are not strictly cryogen-free as they are still based on helium gas circulation through the sample space. We designed a prototype of a gas gap heat switch (GGHS) that allows a thermal management of a completely cryogen-free magnet system, with no helium losses. The idea relies on a parallel cooling path to a variable temperature insert (VTI) of a magnetic properties measurement system under development at Inter-University Accelerator Centre. A Gifford-McMahon cryocooler (1.5 W @ 4.2 K) would serve primarily as the cold source of the superconducting magnet, dedicating 1 W to this cooling, under quite conservative safety factors. The remaining cooling power (0.5 W) is to be diverted towards a VTI through a controlled GGHS that was designed and built with a 80 μm gap width. The built GGHS thermal performance was measured at 4 K, using helium as the exchange gas, and its conductance is compared both with a previously developed analytical model and a finite element method. Lessons learned lead to a new and more functional prototype yet to be reported. (paper)

  18. Giants for cryogenics

    CERN Multimedia

    2009-01-01

    It takes 130 tonnes of liquid helium to cool down the LHC. In some situations—during a shutdown, for instance—this enormous volume of helium has to be removed from the machine and stored elsewhere. While this is a straightforward operation from the technical point of view, in logistical terms storing such a huge amount of the special element that is helium is far from trivial. Until recently, CERN had the capacity for storing up to 52 tonnes of helium in gas form, i.e. 40% of the total needed by the LHC, using the storage tanks that can be seen in the vicinity of some of the experiment sites. As of the middle of June, two new storage tanks, among the largest in the world, are now located at Point 18. Each holding up to 128 000 litres of liquid helium, for a total of 28 tonnes between the two of them, the new tanks have increased CERN’s helium storage capacity by 20%, to reach 60%. The goal is to have storage capacity at 100% by 2010, with the arrival of four mor...

  19. Cryogenic Fluid Management Facility

    Science.gov (United States)

    Eberhardt, R. N.; Bailey, W. J.

    1985-01-01

    The Cryogenic Fluid Management Facility is a reusable test bed which is designed to be carried within the Shuttle cargo bay to investigate the systems and technologies associated with the efficient management of cryogens in space. Cryogenic fluid management consists of the systems and technologies for: (1) liquid storage and supply, including capillary acquisition/expulsion systems which provide single-phase liquid to the user system, (2) both passive and active thermal control systems, and (3) fluid transfer/resupply systems, including transfer lines and receiver tanks. The facility contains a storage and supply tank, a transfer line and a receiver tank, configured to provide low-g verification of fluid and thermal models of cryogenic storage and transfer processes. The facility will provide design data and criteria for future subcritical cryogenic storage and transfer system applications, such as Space Station life support, attitude control, power and fuel depot supply, resupply tankers, external tank (ET) propellant scavenging, and ground-based and space-based orbit transfer vehicles (OTV).

  20. Cryogen therapy of skin cancer

    International Nuclear Information System (INIS)

    Zikiryakhodjaev, D.Z.; Sanginov, D.R.

    2001-01-01

    In this chapter authors studied the cure of skin cancer in particular cryogen therapy of skin cancer. They noted that cryogen therapy of skin cancer carried new possibilities and improved results of neoplasms treatment

  1. Five second helium neutral beam injection using argon-frost cryopumping techniques

    International Nuclear Information System (INIS)

    Phillips, J.C.; Kellman, D.H.; Hong, R.; Kim, J.; Laughon, G.M.

    1995-01-01

    High power helium neutral beams for the heating of tokamak discharges can now be provided for 5 s by using argon cryopumping (of the helium gas) in the beamlines. The DIII-D neutral beam system has routinely provided up to 20 MW of deuterium neutral beam heating in support of experiments on the DIII-D tokamak. Operation of neutral beams with helium has historically presented a problem in that pulse lengths have been limited to 500 ms due to reliance solely on volume pumping of the helium gas. Helium is not condensed on the cryopanels. A system has now been installed to deposit a layer of argon frost on the DIII-D neutral beam cryopanels, between tokamak injection pulses. The layer serves to trap helium on the cryopanels providing sufficient pumping speed for 5 s helium beam extraction. The argon frosting hardware is now present on two of four DIII-D neutral beamlines, allowing injection of up to 6 MW of helium neutral beams per discharge, with pulse lengths of up to 5 s. The argon frosting system is described, along with experimental results demonstrating its effectiveness as a method of economically extending the capabilities of cryogenic pumping panels to allow multi-second helium neutral beam injection

  2. The cryogenic system for the superconducting solenoid magnet of the CMS experiment

    CERN Document Server

    Delikaris, D; Passardi, Giorgio; Lottin, J C; Lottin, J P; Lyraud, C

    1998-01-01

    The design concept of the CMS experiment, foreseen for the Large Hadron Collider (LHC) project at CERN, is based on a superconducting solenoid magnet. The large coil will be made of a four layers winding generating the 4 T uniform magnetic induction required by the detector. The length of the solenoid is 13 m with an inner diameter of 5.9 m. The mass kept at liquid helium temperature totals 220 t and the electromagnetic stored energy is 2.7 GJ. The windings are indirectly cooled with a liquid helium flow driven by a thermosyphon effect. The external cryogenic system consists of a 1.5 kW at 4.5 K (entropy equivalent) cryoplant including an additional liquid nitrogen precooling unit and a 5000 litre liquid helium buffer. The whole magnet and cryogenic system will be tested at the surface by 2003 before final installation in the underground area of LHC.

  3. Cryogenic system for the Energy Recovery Linac and vertical test facility at BNL

    International Nuclear Information System (INIS)

    Than, R.; Soria, V.; Lederle, D.; Orfin, P.; Porqueddu, R.; Talty, P.; Zhang, Y.; Tallerico, T.; Masi, L.

    2011-01-01

    A small cryogenic system and warm helium vacuum pumping system provides cooling to either the Energy Recovery Linac's (ERL) cryomodules that consist of a 5-cell cavity and an SRF gun or a large Vertical Test Dewar (VTD) at any given time. The cryogenic system consists of a model 1660S PSI piston plant, a 3800 liter storage dewar, subcooler, a wet expander, a 50 g/s main helium compressor, and a 170 m 3 storage tank. A system description and operating plan of the cryogenic plant and cryomodules is given. The cryogenic system for ERL and the Vertical Test Dewar has a plant that can produce the equivalent of 300W at 4.5K with the addition of a wet expander 350 W at 4.5K. Along with this system, a sub-atmospheric, warm compression system provides pumping to produce 2K at the ERL cryomodules or the Vertical Test Dewar. The cryogenic system for ERL and the Vertical Test Dewar makes use of existing equipment for putting a system together. It can supply either the ERL side or the Vertical Test Dewar side, but not both at the same time. Double valve isolation on the liquid helium supply line allows one side to be warmed to room temperature and worked on while the other side is being held at operating temperature. The cryogenic system maintain the end loads from 4.4K to 2K or colder depending on capacity. Liquid helium storage dewar capacity allows ERL or the VTD to operate above the plant's capacity when required and ERL cryomodules ballast reservoirs and VTD reservoir allows the end loads to operate on full vacuum pump capacity when required.

  4. Solid-cryogen-stabilized, cable-in-conduit (CIC) superconducting cables

    Science.gov (United States)

    Voccio, J. P.; Michael, P. C.; Bromberg, L.; Hahn, S.

    2015-12-01

    This paper considers the use of a solid cryogen as a means to stabilize, both mechanically and thermally, magnesium diboride (MgB2) superconducting strands within a dual-channel cable-in-conduit (CIC) cable for use in AC applications, such as a generator stator winding. The cable consists of two separate channels; the outer channel contains the superconducting strands and is filled with a fluid (liquid or gas) that becomes solid at the device operating temperature. Several options for fluid will be presented, such as liquid nitrogen, hydrocarbons and other chlorofluorocarbons (CFCs) that have a range of melting temperatures and volumetric expansions (from solid at operating temperature to fixed volume at room temperature). Implications for quench protection and conductor stability, enhanced through direct contact with the solid cryogen, which has high heat capacity and thermal conductivity (compared with helium gas), will be presented. Depending on the cryogen, the conductor will be filled initially either with liquid at atmospheric conditions or a gas at high pressure (∼100 atm). After cooldown, the cryogen in the stranded-channel will be solid, essentially locking the strands in place, preventing strand motion and degradation due to mechanical deformation while providing enhanced thermal capacity for stability and protection. The effect of cryogen porosity is also considered. The relatively high heat capacity of solid cryogens at these lower temperatures (compared to gaseous helium) enhances the thermal stability of the winding. During operation, coolant flow through the open inner channel will minimize pressure drop.

  5. Cryogenic process simulation

    International Nuclear Information System (INIS)

    Panek, J.; Johnson, S.

    1994-01-01

    Combining accurate fluid property databases with a commercial equation-solving software package running on a desktop computer allows simulation of cryogenic processes without extensive computer programming. Computer simulation can be a powerful tool for process development or optimization. Most engineering simulations to date have required extensive programming skills in languages such as Fortran, Pascal, etc. Authors of simulation code have also usually been responsible for choosing and writing the particular solution algorithm. This paper describes a method of simulating cryogenic processes with a commercial software package on a desktop personal computer that does not require these traditional programming tasks. Applications include modeling of cryogenic refrigerators, heat exchangers, vapor-cooled power leads, vapor pressure thermometers, and various other engineering problems

  6. Cryogenic adsorption of low-concentration hydrogen on charcoal, 5A molecular sieve, sodalite, ZSM-5 and Wessalith DAY

    International Nuclear Information System (INIS)

    Willms, R.S.

    1993-01-01

    The separation of low-concentration hydrogen isotopes from helium is a processing step that is required for ceramic lithium breeding blanket processing. Cryogenic adsorption is one method of effecting this separation. In this study live adsorbents were considered for this purpose: charcoal, 5A molecular sieve, UOP S-115, ZSM-5 and Wessalith DAY. The first two adsorbents exhibit good equilibrium loadings and are shown to be quite effective at adsorbing low-concentration hydrogen isotopes. The latter three adsorbents display considerably lower equilibrium loadings. This study concludes that by using either charcoal or 5A molecular sieve, cryogenic adsorption would be an effective means of separating hydrogen isotopes from helium

  7. Measurement of the fully leptonic cross section and the W`s branching ratios in the ALEPH experiment at LEP2; Mesure de la section efficace totalement leptonique et des rapports d`embranchement des bosons W{+-} dans le cadre de l`experience ALEPH a LEP2

    Energy Technology Data Exchange (ETDEWEB)

    Faif, A.M.G. [CEA Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee]|[Grenoble-1 Univ., 38 (France)

    1998-12-08

    This thesis works is part of the precision tests done at LEP2. The W{+-} boson pairs are produced through e{sup +}e{sup -} collisions. The fully leptonic final states (l{nu}-bar l-bar{nu}) correspond to 10.5 % of the disintegrations. This channel is added to the hadronic and semi-leptonic channels, allowing a constraint on the Standard Model. Data recorded between 1996 and 1998 by the ALEPH detector are used to select the l{nu}-bar l-bar{nu} final states, characterised by two energetic coplanar charged leptons and large transverse missing momentum. The fully leptonic cross-sections are determined in view of the measurement of the W`s branching ratios. Contrary to the TEVATRON`s measurements, the branching ratios are determined without universality constraint on W couplings. Presently, LEP obtains the best precision on the measurement of the W`s branching ratios. No deviation was observed with respect to the Standard Model predictions. (author) 85 refs.

  8. The liquid helium system of ATLAS

    International Nuclear Information System (INIS)

    Nixon, J.M.; Bollinger, L.M.

    1989-01-01

    Starting in 1978 with one small refrigerator and distribution line, the LHe system of ATLAS has gradually grown into a complex network, as required by several enlargements of the superconducting linac. The cryogenic system now comprises 3 refrigerators, 11 helium compressors, /approximately/340 ft. of coaxial LHe transfer line, 3 1000-l dewars, and /approximately/76 LHe valves that deliver steady-state flowing LHe to 16 beam-line cryostats. In normal operation, the 3 refrigerators are linked so as to provide cooling where needed. LHe heat exchangers in distribution lines play an important role. This paper discusses design features of the system, including the logic of the controls that permit the coupled refrigerators to operate stably in the presence of large and sudden changes in heat load. 8 refs., 3 figs

  9. Photoionization of helium dimers; Photoionisation von Heliumdimeren

    Energy Technology Data Exchange (ETDEWEB)

    Havermeier, Tilo

    2010-06-09

    The helium dimer is one of the most weakly bound systems in the universe. This makes it an interesting quantum mechanical object for investigation. These Van der Waals Clusters can be produced in an expansion of a cryogenic gas jet through a small nozzle into vacuum. In the present experiment we examine the interaction of He dimers with synchrotron radiation at an energy range from 64 to 78 eV. We observed different pathways leading to single ionization of both He atoms of the dimer compound. This two close standing ions begin now to dissociate in cause of their coulomb potential. All charged fragments were detected in coincidence with a COLTRIMS system. Especially Interatomic Coulombic Decay (ICD) and the two step process (TS1) were clearly identified. Furthermore a distribution of the internuclear distance was obtained from the measured Kinetic Energy Release (KER). (orig.)

  10. Cryogenic system for a superconducting spectrometer

    International Nuclear Information System (INIS)

    Porter, J.

    1983-03-01

    The Heavy Ion Spectrometer System (HISS) relies upon superconducting coils of cryostable, pool boiling design to provide a maximum particle bending field of 3 tesla. This paper describes the cryogenic facility including helium refrigeration, gas management, liquid nitrogen system, and the overall control strategy. The system normally operates with a 4 K heat load of 150 watts; the LN 2 circuits absorb an additional 4000 watts. 80K intercept control is by an LSI 11 computer. Total available refrigeration at 4K is 400 watts using reciprocating expanders at the 20K and 4K level. The minicomputer has the capability of optimizing overall utility input cost by varying operating points. A hybrid of pneumatic, analog, and digital control is successful in providing full time unattended operation. The 7m diameter magnet/cryostat assembly is rotatable through 180 degrees to provide a variety of spectrometer orientations

  11. Automatic PID Control Loops Design for Performance Improvement of Cryogenic Turboexpander

    International Nuclear Information System (INIS)

    Joshi, D.M.; Patel, H.K.; Shah, D.K.

    2015-01-01

    Cryogenics field involves temperature below 123 K which is much less than ambient temperature. In addition, many industrially important physical processes—from fulfilling the needs of National Thermonuclear Fusion programs, superconducting magnets to treatment of cutting tools and preservation of blood cells, require extreme low temperature. The low temperature required for liquefaction of common gases can be obtained by several processes. Liquefaction is the process of cooling or refrigerating a gas to a temperature below its critical temperature so that liquid can be formed at some suitable pressure which is below the critical pressure. Helium liquefier is used for the liquefaction process of helium gas. In general, the Helium Refrigerator/Liquefier (HRL) needs turboexpander as expansion machine to produce cooling effect which is further used for the production of liquid helium. Turboexpanders, a high speed device that is supported on gas bearings, are the most critical component in many helium refrigeration systems. A very minor fault in the operation and manufacturing or impurities in the helium gas can destroy the turboexpander. However, since the performance of expanders is dependent on a number of operating parameters and the relations between them are quite complex, the instrumentation and control system design for turboexpander needs special attention. The inefficiency of manual control leads to the need of designing automatic control loops for turboexpander. Proper design and implementation of the control loops plays an important role in the successful operation of the cryogenic turboexpander. The PID control loops has to be implemented with accurate interlocks and logic to enhance the performance of the cryogenic turboexpander. For different normal and off-normal operations, speeds will be different and hence a proper control method for critical rotational speed avoidance is must. This paper presents the design of PID control loops needed for the

  12. Cryogenic support member

    International Nuclear Information System (INIS)

    Niemann, R.C.; Gonczy, J.D.; Nicol, T.H.

    1987-01-01

    A cryogenic support member is described for restraining a cryogenic system comprising; a rod having a depression at a first end. The rod is made of non-metallic material. The non-metallic material has an effectively low thermal conductivity; a metallic plug; and a metallic sleeve. The plug and the sleeve are shrink-fitted to the depression in the rod and assembled thereto such that the plug is disposed inside the depression of the rod. The sleeve is disposed over the depression in the rod and the rod is clamped therebetween. The shrink-fit clamping the rod is generated between the metallic plug and the metallic sleeve

  13. Spiral 2 cryogenic system overview: Design, construction and performance test

    Energy Technology Data Exchange (ETDEWEB)

    Deschildre, C.; Bernhardt, J.; Flavien, G.; Crispel, S. [Air Liquide Advanced Technologies, Sassenage (France); Souli, M. [GANIL, Caen (France); Commeaux, C. [IPN, Orsay (France)

    2014-01-29

    The new particle accelerator project Spiral 2 at GANIL (“Grand Accélérateur d’Ions Lourds, i.e. National Large Heavy Ion Accelerator) in Caen (France) is a very large installation, intended to serve fundamental research in nuclear physics. The heart of the future machine features a superconductor linear accelerator, delivering a beam until 20Mev/A, which are then used to bombard a matter target. The resulting reactions, such as fission, transfer, fusion, etc. will generate billions of exotic nuclei. To achieve acceleration of the beam, 26 cavities which are placed inside cryomodules at helium cryogenic temperature will be used. AL-AT (Air Liquide Advanced Technologies) takes part to the project by supplying cryogenic plant. The plant includes the liquefier associated to its compressor station, a large dewar, a storage tank for helium gas and transfer lines. In addition, a helium recovery system composed of recovery compressor, high pressure storage and external purifier has been supplied. Customized HELIAL LF has been designed, manufactured and tested by AL-AT to match the refrigeration power need for the Spiral 2 project which is around 1300 W equivalent at 4.5 K.

  14. Cryogenic techniques for large superconducting magnets in space

    Science.gov (United States)

    Green, M. A.

    1989-01-01

    A large superconducting magnet is proposed for use in a particle astrophysics experiment, ASTROMAG, which is to be mounted on the United States Space Station. This experiment will have a two-coil superconducting magnet with coils which are 1.3 to 1.7 meters in diameter. The two-coil magnet will have zero net magnetic dipole moment. The field 15 meters from the magnet will approach earth's field in low earth orbit. The issue of high Tc superconductor will be discussed in the paper. The reasons for using conventional niobium-titanium superconductor cooled with superfluid helium will be presented. Since the purpose of the magnet is to do particle astrophysics, the superconducting coils must be located close to the charged particle detectors. The trade off between the particle physics possible and the cryogenic insulation around the coils is discussed. As a result, the ASTROMAG magnet coils will be operated outside of the superfluid helium storage tank. The fountain effect pumping system which will be used to cool the coil is described in the report. Two methods for extending the operating life of the superfluid helium dewar are discussed. These include: operation with a third shield cooled to 90 K with a sterling cycle cryocooler, and a hybrid cryogenic system where there are three hydrogen-cooled shields and cryostat support heat intercept points.

  15. Tests of cold helium compressors at Fermilab

    International Nuclear Information System (INIS)

    Peterson, T.J.; Fuerst, J.D.

    1987-10-01

    Fermilab has tested two cold helium compressors for possible installation in the satellite refrigerator buildings of the Tevatron cryogenic system. Operating conditions required to obtain an overall Tevatron energy upgrade from 900 to 1000 GeV are (for each of 24 machines): 52 g/s mass flow rate, 0.7 atm inlet pressure, 1.4 atm exhaust pressure. Acceptable efficiency is in the 60% range. Both Creare, Inc., and Cryogenic Consultants, Inc. (CCI), have supplied units for evaluation. The Creare machine is a high speed centrifugal pump/compressor which yielded 60% adiabatic efficiency (including an approximately 20 watt heat leak) with a 1.0 atm inlet pressure and 55 g/s flow rate. Certain mechanical difficulties were present, chiefly the device's inability to withstand two-phase flow. CCI supplied a reciprocating unit which, after initial testing and modification, achieved 59% efficiency with an approximate 35 watt heat leak at a 0.7 atm inlet pressure and 48 g/s flow rate. Although the device lacks the smooth, quiet operating characteristics of a turbomachine, it has endured mechanically throughout testing and is entirely insensitive to two-phase flow

  16. SiPM properties at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Biroth, Maik; Achenbach, Patrick; Thomas, Andreas [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, Mainz (Germany); Downie, Evangeline [George Washington University, DC (United States); Collaboration: A2-Collaboration

    2015-07-01

    At the electron accelerator Mainzer Mikrotron (MAMI) an active target build of polarizable scintillators will be operated at approximately 25 mK. To read out the scintillation light, the photodetectors have to withstand cryogenic temperatures of 4 K and high count rates. Therefore the properties of different types of silicon photomultipliers (SiPMs) were studied at cryogenic temperatures. In liquid nitrogen at 77 K, problems with quenching in Hamamatsu SiPMs and with the protective epoxy layer covering Zecotek SiPMs were observed. Tests with one Zecotek SiPM were successful after removal of the epoxy layer in liquid helium at 4 K and no after-pulses could be observed. Fundamental parameters like break-down voltage, single-pixel gain, crosstalk probability and the dark-count rate were measured and compared to room temperature. The photon detection efficiency was estimated by SiPMs response to short LED pulses. All these parameters were extracted by curve-fitting of SiPM charge spectra with a new analytical function.

  17. High efficiency, variable geometry, centrifugal cryogenic pump

    International Nuclear Information System (INIS)

    Forsha, M.D.; Nichols, K.E.; Beale, C.A.

    1994-01-01

    A centrifugal cryogenic pump has been developed which has a basic design that is rugged and reliable with variable speed and variable geometry features that achieve high pump efficiency over a wide range of head-flow conditions. The pump uses a sealless design and rolling element bearings to achieve high reliability and the ruggedness to withstand liquid-vapor slugging. The pump can meet a wide range of variable head, off-design flow requirements and maintain design point efficiency by adjusting the pump speed. The pump also has features that allow the impeller and diffuser blade heights to be adjusted. The adjustable height blades were intended to enhance the pump efficiency when it is operating at constant head, off-design flow rates. For small pumps, the adjustable height blades are not recommended. For larger pumps, they could provide off-design efficiency improvements. This pump was developed for supercritical helium service, but the design is well suited to any cryogenic application where high efficiency is required over a wide range of head-flow conditions

  18. Cryogenic vacuum pump design

    International Nuclear Information System (INIS)

    Bartlett, A.J.; Lessard, P.A.

    1984-01-01

    This paper is a review of the problems and tradeoffs involved in cryogenic vacuum pump analysis, design and manufacture. Particular attention is paid to the several issues unique to cryopumps, e.g., radiation loading, adsorption of noncondensible gases, and regeneration. A general algorithm for cryopump design is also proposed. 12 references

  19. Cryogenic current leads

    Energy Technology Data Exchange (ETDEWEB)

    Zizek, F.

    1982-01-01

    Theoretical, technical and design questions are examined of cryogenic current leads for SP of magnetic systems. Simplified mathematical models are presented for the current leads. To illustrate modeling, the calculation is made of the real current leads for 500 A and three variants of current leads for 1500 A for the enterprise ''Shkoda.''

  20. Installation and commissioning of a cryogen distribution system for the TPS project

    Science.gov (United States)

    Tsai, H. H.; Hsiao, F. Z.; Li, H. C.; Lin, M. C.; Wang, C.; Liao, W. R.; Lin, T. F.; Chiou, W. S.; Chang, S. H.; Chuang, P. S. D.

    2016-07-01

    A cryogen distribution system was installed and commissioned to transfer liquid nitrogen (LN2) and liquid helium (LHe) from storage dewars to superconducting radio-frequency (SRF) cavities for the 3-GeV Taiwan Photon Source (TPS) project. The cryogen distribution system comprises one distribution valve box (DVB), four control valve boxes (CVB) and seven sections of multichannel transfer line (MCL). The DVB distributes the LHe and LN2 to the CVB, and then to the SRF cavities through independent vacuum-jacketed transfer lines. The vaporized GHe and GN2 from the cryomodules are collected via the MCL. The cryogen distribution system was installed and commissioned from October 2014 to the end of March 2015. This paper presents the installation, pre-commissioning and commissioning of the cryogen distribution system, and describes the heat load test. Thermal acoustic oscillation (TAO) was found in the GHe process line; this phenomenon and its solution are also presented and discussed.

  1. A VME based cryogenic data acquisition and control system (CRYO-DACS)

    International Nuclear Information System (INIS)

    Antony, Joby; Rajkumar; Datta, T.S.

    2005-01-01

    This report describes a newly developed VME based data acquisition and control system named CRYO-DACS for acquiring and controlling various analog and digital cryogenic parameters from equipment's like beam-line cryostats, Helium compressors, liquefier, cryogenic distribution line etc. A new central control room has been set-up for the remote controls and monitoring. The system monitors various analog parameters like temperature, pressure, vacuum and cryogenic fluid levels inside the cryostats and performs closed loop controls of cryogen valves. The hardware architecture of CRYO-DACS is multi-crate distributed VME, all linked by workstation clients in 100 Mb/s LAN for distributed logging, historical trending, analysis, alarm management and control GUIs. (author)

  2. SAFE AND FAST QUENCH RECOVERY OF LARGE SUPERCONDUCTING SOLENOIDS COOLED BY FORCED TWO-PHASE HELIUM FLOW

    International Nuclear Information System (INIS)

    Jia, L.X.

    1999-01-01

    The cryogenic characteristics in energy extraction of the four fifteen-meter-diameter superconducting solenoids of the g-2 magnet are reported in this paper. The energy extraction tests at full-current and half-current of its operating value were deliberately carried out for the quench analyses and evaluation of the cryogenic system. The temperature profiles of each coil mandrel and pressure profiles in its helium cooling tube during the energy extraction are discussed. The low peak temperature and pressure as well as the short recovery time indicated the desirable characteristics of the cryogenic system

  3. D0 Silicon Upgrade: Commissioning Test Results for D-Zero's Helium Refrigerator

    International Nuclear Information System (INIS)

    Rucinski, Russ

    1997-01-01

    The test objectives are: (1) Make liquid helium and measure refrigerator capacity; (2) Measure liquid helium dewar heat leak, transfer line heat leak, and liquid nitrogen consumption rates; (3) Operate all cryogenic transfer lines; (4) Get some running time on all components; (5) Debug mechanical components, instrumentation, DMACs user interface, tune loops, and otherwise shake out any problems; (6) Get some operating time in to get familiar with system behavior; (7) Revise and/or improve operating procedures to actual practice; and (8) Identify areas for future improvement. D-Zero's stand alone helium refrigerator (STAR) liquified helium at a rate of 114 L/hr. This is consistent with other STAR installations. Refrigeration capacity was not measured due to lack of a calibrated heat load. Measured heat leaks were within design values. The helium dewar loss was measured at 2 to 4 watts or 9% per day, the solenoid and VLPC helium transfer lines had a heat leak of about 20 watts each. The liquid nitrogen consumption rates of the mobile purifier, STAR, and LN2 subcooler were measured at 20 gph, 20 to 64 gph, and 3 gph respectively. All cryogenic transfer lines including the solenoid and visible light photon counter (VLPC) transfer lines were cooled to their cryogenic operating temperatures. This included independent cooling of nitrogen shields and liquid helium components. No major problems were observed. The system ran quite well. Many problems were identified and corrected as they came up. Areas for improvement were noted and will be implemented in the future. The instrumentation and control system operated commendably during the test. The commissioning test run was a worthwhile and successful venture.

  4. Submersible fans and pumps for cryogenic fluids

    International Nuclear Information System (INIS)

    Mark, J.W.

    1986-01-01

    Submersible electric motor driven fans of three sizes have been designed, built and operated at 21 0 K at the Stanford Linear Accelerator Center. The largest is a 100-mm diameter, 2 stage vaneaxial fan with a nominal capacity of 6 L/s at 2 m head. It is driven by a 4 pole, 3 phase induction motor that runs at 1750 rpm. The next smaller one is an 85-mm diameter centrifugal pump. It pumps 3 L/s at a head of 5 m. The third is a 75-mm single stage vaneaxial fan with a nominal capacity is 3 L/s at a head of 2 m. The 85-mm pump and the 75-mm fan are driven by 2 pole, 3 phase induction motors running at 3550 rpm. The motors were modified to operate submerged in the cryogenic fluid. The pumps have been operated in liquid hydrogen, liquid deuterium, and pressurized helium gas at 21 0 K. They can also operate with denser fluids such as liquid nitrogen, but rotational speed, capacity, and head will be reduced. They have been operated while submerged in liquid helium

  5. Development of a cryogenic EOS capability for the Z Pulsed Radiation Source: Goals and accomplishments of FY97 LDRD project

    International Nuclear Information System (INIS)

    Hanson, D.L.; Johnston, R.R.; Asay, J.R.

    1998-03-01

    Experimental cryogenic capabilities are essential for the study of ICF high-gain target and weapons effects issues involving dynamic materials response at low temperatures. This report describes progress during the period 2/97-11/97 on the FY97 LDRD project ''Cryogenic EOS Capabilities on Pulsed Radiation Sources (Z Pinch)''. The goal of this project is the development of a general purpose cryogenic target system for precision EOS and shock physics measurements at liquid helium temperatures on the Z accelerator Z-pinch pulsed radiation source. Activity during the FY97 LDRD phase of this project has focused on development of a conceptual design for the cryogenic target system based on consideration of physics, operational, and safety issues, design and fabrication of principal system components, construction and instrumentation of a cryogenic test facility for off-line thermal and optical testing at liquid helium temperatures, initial thermal testing of a cryogenic target assembly, and the design of a cryogenic system interface to the Z pulsed radiation source facility. The authors discuss these accomplishments as well as elements of the project that require further work

  6. Cryogenics for the MuCool Test Area (MTA)

    International Nuclear Information System (INIS)

    Darve, Christine; Norris, Barry; Pei, Liujin

    2006-01-01

    MuCool Test Area (MTA) is a complex of buildings at Fermi National Accelerator Laboratory, which are dedicated to operate components of a cooling cell to be used for Muon Collider and Neutrino Factory R and D. The long-term goal of this facility is to test ionization cooling principles by operating a 25-liter liquid hydrogen (LH2) absorber embedded in a 5 Tesla superconducting solenoid magnet. The MTA solenoid magnet will be used with RF cavities exposed to a high intensity beam. Cryogens used at the MTA include LHe, LN2 and LH2. The latter dictates stringent system design for hazardous locations. The cryogenic plant is a modified Tevatron refrigerator based on the Claude cycle. The implementation of an in-house refrigerator system and two 300 kilowatt screw compressors is under development. The helium refrigeration capacity is 500 W at 14 K. In addition the MTA solenoid magnet will be batch-filled with LHe every 2 days using the same cryo-plant. This paper reviews cryogenic systems used to support the Muon Collider and Neutrino Factory R and D programs and emphasizes the feasibility of handling cryogenic equipment at MTA in a safe manner

  7. Cryogenic technology review of cold neutron source facility for localization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hun Cheol; Park, D. S.; Moon, H. M.; Soon, Y. P. [Daesung Cryogenic Research Institute, Ansan (Korea); Kim, J. H. [United Pacific Technology, Inc., Ansan (Korea)

    1998-02-01

    This Research is performed to localize the cold neutron source(CNS) facility in HANARO and the report consists of two parts. In PART I, the local and foreign technology for CNS facility is investigated and examined. In PART II, safety and licensing are investigated. CNS facility consists of cryogenic and warm part. Cryogenic part includes a helium refrigerator, vacuum insulated pipes, condenser, cryogenic fluid tube and moderator cell. Warm part includes moderator gas control, vacuum equipment, process monitoring system. Warm part is at high level as a result of the development of semiconductor industries and can be localized. However, even though cryogenic technology is expected to play a important role in developing the 21st century's cutting technology, it lacks of specialists and the research facility since the domestic market is small and the research institutes and government do not recognize the importance. Therefore, it takes a long research time in order to localize the facility. The safety standard of reactor for hydrogen gas in domestic nuclear power regulations is compared with that of the foreign countries, and the licensing method for installation of CNS facility is examined. The system failure and its influence are also analyzed. 23 refs., 59 figs., 26 tabs. (Author)

  8. The Fermilab CMTF cryogenic distribution remote control system

    Energy Technology Data Exchange (ETDEWEB)

    Pei, L.; Theilacker, J.; Klebaner, A.; Martinez, A.; Bossert, R. [Fermi National Accelerator Laboratory Batavia, IL, 60510 (United States)

    2014-01-29

    The Cryomodule Test Facility (CMTF) is able to provide the necessary test bed for measuring the performance of Superconducting Radio Frequency (SRF) cavities in a cryomodule (CM). The CMTF have seven 300 KW screw compressors, two liquid helium refrigerators, and two Cryomodule Test Stands (CMTS). CMTS1 is designed for 1.3 GHz cryomodule operating in a pulsed mode (PM) and CMTS2 is for cryomodule operating in Half-Wave (HW) and Continuous Wave (CW) mode. Based on the design requirement, each subsystem has to be far away from each other and be placed in distant locations. Therefore choosing Siemens Process Control System 7-400, DL205 PLC, Synoptic and Fermilab ACNET are the ideal choices for CMTF cryogenic distribution real-time remote control system. This paper presents a method which has been successfully used by many Fermilab distribution cryogenic real-time remote control systems.

  9. Cryogenic distribution system for ITER proto-type cryoline test

    International Nuclear Information System (INIS)

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

    2012-01-01

    Design validation for ITER cryoline will be carried out by proto-type test on cryoline. The major objectives of the test will be to ensure the mechanical integrity, reliability, thermal stress and heat load as well as checking of assembly and fabrication procedures. The cryogenics system has to satisfy the functional operating scenario of the cryoline. Cryoplant, distribution box (DB) including liquid helium (LHe) tank constitute the cryogenic system for the test. Conceptual system architecture is proposed with a commercially available refrigerator/liquefier and custom designed DB housing cold compressor, cold circulator as well as phase separator with sub-merged heat exchanger. System level optimization, mainly with DB and LHe tank with options, has been studied to minimize the cold power required for the system. Aspen HYSYS is used for the purpose of process simulation. The paper describes the system architecture and the optimized design as well as process simulation with associated results. (author)

  10. Cryogenic Beam Screens for High-Energy Particle Accelerators

    CERN Document Server

    Baglin, V; Tavian, L; van Weelderen, R

    2013-01-01

    Applied superconductivity has become a key enabling technology for high-energy particle accelerators, thus making them large helium cryogenic systems operating at very low temperature. The circulation of high-intensity particle beams in these machines generates energy deposition in the first wall through different processes. For thermodynamic efficiency, it is advisable to intercept these beam-induced heat loads, which may be large in comparison with cryostat heat in-leaks, at higher temperature than that of the superconducting magnets of the accelerator, by means of beam screens located in the magnet apertures. Beam screens may also be used as part of the ultra-high vacuum system of the accelerator, by sheltering the gas molecules cryopumped on the beam pipe from impinging radiation and thus avoiding pressure runaway. Space being extremely tight in the magnet apertures, cooling of the long, slender beam screens also raises substantial problems in cryogenic heat transfer and fluid flow. We present sizing rule...

  11. The development of the advanced cryogenic radiometer facility at NRC

    Science.gov (United States)

    Gamouras, A.; Todd, A. D. W.; Côté, É.; Rowell, N. L.

    2018-02-01

    The National Research Council (NRC) of Canada has established a next generation facility for the primary realization of optical radiant power. The main feature of this facility is a new cryogenic electrical substitution radiometer with a closed-cycle helium cryocooler. A monochromator-based approach allows for detector calibrations at any desired wavelength. A custom-designed motion apparatus includes two transfer standard radiometer mounting ports which has increased our measurement capability by allowing the calibration of two photodetectors in one measurement cycle. Measurement uncertainties have been improved through several upgrades, including newly designed and constructed transimpedance amplifiers for the transfer standard radiometers, and a higher power broadband light source. The most significant improvements in uncertainty arise from the enhanced characteristics of the new cryogenic radiometer including its higher cavity absorptance and reduced non-equivalence effects.

  12. Operational Experience with a Cryogenic Axial-Centrifugal Compressor

    CERN Document Server

    Decker, L; Löhlein, K; Purtschert, W; Ziegler, B L; Lebrun, P; Tavian, L; Brunovsky, I; Tucek, L

    1998-01-01

    The Large Hadron Collider (LHC), presently under construction at CERN, requires large refrigeration capacity at 1.8 K. Compression of gaseous helium at cryogenic temperatures is therefore inevitable. Together with subcontractors, Linde Kryotechnik has developed a prototype machine. This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating at ambient temperature. Integrated in a test facility for superconducting magnets the machine has been commissioned without major problems and successfully gone through the acceptance test in autumn 1995. Subsequent steps were initiated to improve efficiency of this prototype. This paper describes operating experience gained so far and reports on measured performance prior to and after constructional modifications.

  13. Helium refrigerator for 'SULTAN'

    International Nuclear Information System (INIS)

    Arpagaus, M.; Erlach, H.; Quack, H.

    1984-01-01

    The authors describe the helium refrigerator designed for the SULTAN test facility. SULTAN (Supraleiter-Testanlage) is intended to serve for the developments and testing of high field superconducting magnets. These magnets are needed mainly for future applications in nuclear fusion. (Auth.)

  14. Cosmological helium production simplified

    International Nuclear Information System (INIS)

    Bernstein, J.; Brown, L.S.; Feinberg, G.

    1988-01-01

    We present a simplified model of helium synthesis in the early universe. The purpose of the model is to explain clearly the physical ideas relevant to the cosmological helium synthesis, in a manner that does not overlay these ideas with complex computer calculations. The model closely follows the standard calculation, except that it neglects the small effect of Fermi-Dirac statistics for the leptons. We also neglect the temperature difference between photons and neutrinos during the period in which neutrons and protons interconvert. These approximations allow us to express the neutron-proton conversion rates in a closed form, which agrees to 10% accuracy or better with the exact rates. Using these analytic expressions for the rates, we reduce the calculation of the neutron-proton ratio as a function of temperature to a simple numerical integral. We also estimate the effect of neutron decay on the helium abundance. Our result for this quantity agrees well with precise computer calculations. We use our semi-analytic formulas to determine how the predicted helium abundance varies with such parameters as the neutron life-time, the baryon to photon ratio, the number of neutrino species, and a possible electron-neutrino chemical potential. 19 refs., 1 fig., 1 tab

  15. Local Cryogenics for the SIS100 at FAIR

    International Nuclear Information System (INIS)

    Eisel, T; Kauschke, M; Kollmus, H; Streicher, B; Chorowski, M; Iluk, A; Malcher, K; Polinski, J

    2015-01-01

    In the coming years a new international accelerator Facility for Antiproton and Ion Research (FAIR), one of the largest research projects worldwide, will be build close to Darmstadt in Germany. FAIR will provide antiproton and ion beams with unprecedented intensity and quality. One of its major accelerators will be a synchrotron called SIS100 having a circumference of about 1100 meters. The SIS100 tunnel will house a complex cryogenic system supplying up to 20 kW cooling capacity @ 4.5 K to about 300 superconducting fast ramped magnets and other physics equipment. The planned SIS100 local cryogenic system can be principally divided into three sections each fed from a separate Feed Box. Every Feed Box supplies 4.5 K helium for magnet, vacuum chamber, cryo collimator, current lead and bus-bar cooling as well as 50 K helium for the current lead and thermal shield cooling, independently to two sixth of the ring. Each sixth of the ring, so called sextant, consists of a cold arc and a straight warm section. By-pass Lines circumvent the straight warm sections of the sextants, where warm equipment (e.g. normal conducting cavities and magnets) is located. Between the warm equipment, are superconducting magnets located which also need to be supplied from the By-pass Lines with helium and cold electrical connections. The By-pass Lines are Polish in-kind contribution, coordinated by the Jagiellonian University of Krakow and will be designed, manufactured and commissioned by the Wroclaw University of Technology. In this paper the SIS100 local cryogenic system will be described with focus on the By-pass Lines and on magnet cooling including the balancing of differences between dipole and quadrupole circuits and the coping with dynamic loads. (paper)

  16. Etude des sections efficaces et des asymétries di-leptoniques à LEP2. Contraintes sur la physique au-delà du Modèle Standard

    CERN Document Server

    De Bonnis, Isabelle

    I describe in this HDR the scientific works that I have done since my PhD, defended in 1994. The first part of these works was devoted to the development of detectors within the BaBar experiment. The second part, more extensively described here, was the study of the di-leptonic events produced in the ALEPH experiment at LEP2. In the BaBar experiment, I initially contributed to the feasibility study of a Cerenkov counter dedicated to the identification of charged particles. I had then the responsibility of the construction of a wire chamber for the monitoring of the gain, installed in the gas distribution system of the BaBar drift chamber. These activities included design and simulation of instruments as well as analysis of tests data. Then, I participated to the LEP2 data analysis by measuring cross-sections and forward-backward asymmetries of the di-leptonic processes. I made the interpretation of these measurements under various scenarios of new physics beyond the Standard Model, such as four fermions conta...

  17. ARIEL E-linac Cryogenic System: Commissioning and First Operational Experience

    International Nuclear Information System (INIS)

    Koveshnikov, A; Bylinskii, I; Hodgson, G; Kishi, D; Laxdal, R; Ma, Y; Nagimov, R; Yosifov, D

    2015-01-01

    The Advanced Rare IsotopE Laboratory (ARIEL) is a major expansion of the Isotope Separator and Accelerator (ISAC) facility at TRIUMF. A key part of the ARIEL project is a 10 mA 50 MeV continuous-wave superconducting radiofrequency (SRF) electron linear accelerator (e-linac). The 1.3 GHz SRF cavities are operated at 2 K. HELIAL LL helium liquefier by Air Liquide Advanced Technologies (ALAT) with a tuneable liquid helium (LHe) production was installed and commissioned in Q4’2013 [1]. It provides 4 K liquid helium to one injector and one accelerator cryomodules that were installed and tested in 2014. The 4 K to 2 K liquid helium transition is achieved on-board of each cryomodule. The cryoplant, LHe and LN2 distributions, sub-atmospheric (S/A) system and cryomodules were successfully commissioned and integrated into the e-linac cryogenic system. Required pressure regulation for both 4 K cryoplant in the Dewar and 2 K with the S/A system was achieved under simulated load. Final integration tests confirmed overall stable performance of the cryogenic system with two cryomodules installed. The paper presents details of the cryogenic system commissioning tests as well as highlights of the initial operational experience. (paper)

  18. Weldability of thermally grain-refined Fe-12Ni-0.25Ti for cryogenic structural applications

    International Nuclear Information System (INIS)

    Williams, D.E.

    1980-02-01

    The weldability of a research alloy designed for structural use in liquid helium temperature, cryogenic environments was investigated. Plates of iron-12 weight percent nickel-0.25 weight percent titanium were grain refined by the four-step, grain refining thermal treatment developed for this alloy and welded with Inconel Number 92 weld wire using the Gas Metal Arc (GMA) welding process with argon-15% helium gas shielding. Both a single pass and a double-sided, 2 pass electron beam (EB) weld were also made without filler metal addition. Weldments were radiographed and sectioned and the charpy V-notch specimens removed were tested at liquid nitrogen and helium temperatures

  19. Research and development of a helium-4 based solar neutrino detector

    International Nuclear Information System (INIS)

    Lanou, R.E.; Maris, H.J.; Seidel, G.M.

    1990-12-01

    We report on work accomplished in the first 30 months of a research and development program to investigate the feasibility of a new technique to detect solar neutrinos in superfluid helium. Accomplishments include the successful completion of design, construction and operation of the entire cryogenic, mechanical and electronic apparatus. During the last several months we have begun a series of experiments in superfluid helium to test the method. Experimental results include the first observation of the combined physical processes essential to the detection technique: ballistic roton generation by energetic charged particles, quantum evaporation of helium at a free surface and bolometric detection of the evaporated helium by physisorption on a cold silicon wafer. Additional results are also presented

  20. The commissioning of the instrumentation for the LHC tunnel cryogenics

    CERN Document Server

    Avramidou, R; Bamis, C; Casas-Cubillos, J; Dragoneas, A; Fampris, X; Fernandez-Penacoba, G; Gomes, P; Gousiou, E; Jeanmonod, N; Karagiannis, F; Koumparos, A; Leontsinis, S; Lopez-Lorente, A; Patsouli, A; Polychroniadis, I; Suraci, A; Theodoropoulos, G; Vauthier, N; Vottis, C

    2007-01-01

    The Large Hadron Collider (LHC) at CERN is a superconducting accelerator and proton-proton collider of circumference of 27 km, lying about 100 m underground. Its operation relies on 1232 superconducting dipoles with a field of 8.3 T and 392 superconducting quadrupoles with a field gradient of 223 T/m powered at 11.8 kA and operating in superfluid helium at 1.9 K. This paper describes the cryogenic instrumentation commissioning, the challenges and the project organization based on our 2.5 years experience.

  1. Cryogenic vacuum pumping at the LBL 88-inch cyclotron

    International Nuclear Information System (INIS)

    Elo, D.; Morris, D.; Clark, D.J.; Gough, R.A.

    1978-09-01

    A cryogenic vacuum pumping panel has been in operation at the 88-inch cyclotron since 1974. The nude pumping panel is located in the acceleration chamber. The pumping surface consists of tubing cooled to 20 0 K by a closed loop helium refrigeration system. The pumping surfaces are shielded from radiation heat loads and water vapors by liquid nitrogen cooled baffles. The panel was designed for an average pumping speed of 14,000 liters/sec. for air. This approximately tripled the total effective pumping on the acceleration chamber from the existing diffusion pumped system, significantly reducing charge exchange losses of heavy ions during acceleration. Design, installation and performance characteristics are described

  2. Cryogenic propellant management: Integration of design, performance and operational requirements

    Science.gov (United States)

    Worlund, A. L.; Jamieson, J. R., Jr.; Cole, T. W.; Lak, T. I.

    1985-01-01

    The integration of the design features of the Shuttle elements into a cryogenic propellant management system is described. The implementation and verification of the design/operational changes resulting from design deficiencies and/or element incompatibilities encountered subsequent to the critical design reviews are emphasized. Major topics include: subsystem designs to provide liquid oxygen (LO2) tank pressure stabilization, LO2 facility vent for ice prevention, liquid hydrogen (LH2) feedline high point bleed, pogo suppression on the Space Shuttle Main Engine (SSME), LO2 low level cutoff, Orbiter/engine propellant dump, and LO2 main feedline helium injection for geyser prevention.

  3. Cryogenic surface ion traps

    International Nuclear Information System (INIS)

    Niedermayr, M.

    2015-01-01

    Microfabricated surface traps are a promising architecture to realize a scalable quantum computer based on trapped ions. In principle, hundreds or thousands of surface traps can be located on a single substrate in order to provide large arrays of interacting ions. To this end, trap designs and fabrication methods are required that provide scalable, stable and reproducible ion traps. This work presents a novel surface-trap design developed for cryogenic applications. Intrinsic silicon is used as the substrate material of the traps. The well-developed microfabrication and structuring methods of silicon are utilized to create simple and reproducible traps. The traps were tested and characterized in a cryogenic setup. Ions could be trapped and their life time and motional heating were investigated. Long ion lifetimes of several hours were observed and the measured heating rates were reproducibly low at around 1 phonon per second at a trap frequency of 1 MHz. (author) [de

  4. Flexible cryogenic conduit

    International Nuclear Information System (INIS)

    Brindza, P.D.; Wines, R.R.; Takacs, J.J.

    1999-01-01

    A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament

  5. Cryogenics for SMES

    International Nuclear Information System (INIS)

    McIntosh, G.E.

    1981-01-01

    A wide-ranging study of superconducting magnetic energy storage (SMES) structural and cryogenic requirements was made. Concepts and computational methods have been developed for all of the major problems in these areas. Design analyses have been made to provide more detailed information on some items and experimental work has been performed to create data bases in the areas of superfluid heat transfer, superfluid dielectric properties, heat transfer from conductors, and in the thermal and mechanical properties of materials at low temperatures. In most cases optimum solutions have not been made because of the developing nature of the overall study but methodology for optimization has been worked out for essentially all SMES cryogenic and structural elements. The selection of 1.8 K cooling and all aluminum systems in bedrock continues to be the best choice

  6. Cryogenic treatment of gas

    Science.gov (United States)

    Bravo, Jose Luis [Houston, TX; Harvey, III, Albert Destrehan; Vinegar, Harold J [Bellaire, TX

    2012-04-03

    Systems and methods of treating a gas stream are described. A method of treating a gas stream includes cryogenically separating a first gas stream to form a second gas stream and a third stream. The third stream is cryogenically contacted with a carbon dioxide stream to form a fourth and fifth stream. A majority of the second gas stream includes methane and/or molecular hydrogen. A majority of the third stream includes one or more carbon oxides, hydrocarbons having a carbon number of at least 2, one or more sulfur compounds, or mixtures thereof. A majority of the fourth stream includes one or more of the carbon oxides and hydrocarbons having a carbon number of at least 2. A majority of the fifth stream includes hydrocarbons having a carbon number of at least 3 and one or more of the sulfur compounds.

  7. Chemiluminescence in cryogenic matrices

    Science.gov (United States)

    Lotnik, S. V.; Kazakov, Valeri P.

    1989-04-01

    The literature data on chemiluminescence (CL) in cryogenic matrices have been classified and correlated for the first time. The role of studies on phosphorescence and CL at low temperatures in the development of cryochemistry is shown. The features of low-temperature CL in matrices of nitrogen and inert gases (fine structure of spectra, matrix effects) and the data on the mobility and reactivity of atoms and radicals at very low temperatures are examined. The trends in the development of studies on CL in cryogenic matrices, such as the search for systems involving polyatomic molecules and extending the forms of CL reactions, are followed. The reactions of active nitrogen with hydrocarbons that are accompanied by light emission and CL in the oxidation of carbenes at T >= 77 K are examined. The bibliography includes 112 references.

  8. SNS Central Helium Liquefier spare Carbon Bed installation and commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Degraff, Brian D. [ORNL; Howell, Matthew P. [ORNL; Kim, Sang-Ho [ORNL; Neustadt, Thomas S. [ORNL

    2017-07-01

    The Spallation Neutron Source (SNS) Central Helium Liquefier (CHL) at Oak Ridge National Laboratory (ORNL) has been without major operations downtime since operations were started back in 2006. This system utilizes a vessel filled with activated carbon as the final major component to remove oil vapor from the compressed helium circuit prior to insertion into the system's cryogenic cold box. The need for a spare carbon bed at SNS due to the variability of carbon media lifetime calculation to adsorption efficiency will be discussed. The fabrication, installation and commissioning of this spare carbon vessel will be presented. The novel plan for connecting the spare carbon vessel piping to the existing infrastructure will be presented.

  9. EPICS based control system for cryogenic plant at VECC

    International Nuclear Information System (INIS)

    Panda, Umashankar; Pal, Sandip; Mandal, Anupam; Dey, Ranadhir

    2012-01-01

    Cryogenic Plant of Variable Energy Cyclotron Centre consists of two Helium refrigerators (250W and 415W at the rate 4.5K), valve box with sub-cooler and associated sub systems like pure gas storage, helium purifier and impure gas recovery etc. The system also consists of 3.1K liters of liquid Nitrogen (LN 2 ) storage and delivery system. Many of the systems are procured from different suppliers and some are also developed in house. Due to the variety of systems and suppliers the control philosophy, communication protocols and component is also different. So the Supervisory control and data acquisition (SCADA) module has to be such that it can take care of the variance and bring everything into a common control platform. To solve this purpose EPICS (Experimental Physics and Industrial Control System) architecture has been adopted. EPICS is having the advantage of being open source, flexible and unlimited as compared to the commercial SCADA packages. (author)

  10. Control and operation cost optimization of the HISS cryogenic system

    International Nuclear Information System (INIS)

    Porter, J.; Anderson, D.; Bieser, F.

    1984-01-01

    This chapter describes a control strategy for the Heavy Ion Spectrometer System (HISS), which relies upon superconducting coils of cryostable design to provide a particle bending field of 3 tesla. The control strategy has allowed full time unattended operation and significant operating cost reductions. Microprocessor control of flash boiling style LIN circuits has been successful. It is determined that the overall operating cost of most cryogenic systems using closed loop helium systems can be minimized by properly balancing the total heat load between the helium and nitrogen circuits to take advantage of the non-linearity which exists in the power input to 4K refrigeration characteristic. Variable throughput compressors have the advantage of turndown capability at steady state. It is concluded that a hybrid system using digital and analog input for control, data display and alarms enables full time unattended operation

  11. Operational present status and reliability analysis of the upgraded EAST cryogenic system

    Science.gov (United States)

    Zhou, Z. W.; Y Zhang, Q.; Lu, X. F.; Hu, L. B.; Zhu, P.

    2017-12-01

    Since the first commissioning in 2005, the cryogenic system for EAST (Experimental Advanced Superconducting Tokamak) has been cooled down and warmed up for thirteen experimental campaigns. In order to promote the refrigeration efficiencies and reliability, the EAST cryogenic system was upgraded gradually with new helium screw compressors and new dynamic gas bearing helium turbine expanders with eddy current brake to improve the original poor mechanical and operational performance from 2012 to 2015. Then the totally upgraded cryogenic system was put into operation in the eleventh cool-down experiment, and has been operated for the latest several experimental campaigns. The upgraded system has successfully coped with various normal operational modes during cool-down and 4.5 K steady-state operation under pulsed heat load from the tokamak as well as the abnormal fault modes including turbines protection stop. In this paper, the upgraded EAST cryogenic system including its functional analysis and new cryogenic control networks will be presented in detail. Also, its operational present status in the latest cool-down experiments will be presented and the system reliability will be analyzed, which shows a high reliability and low fault rate after upgrade. In the end, some future necessary work to meet the higher reliability requirement for future uninterrupted long-term experimental operation will also be proposed.

  12. Progress update on cryogenic system for ARIEL E-linac at TRIUMF

    International Nuclear Information System (INIS)

    Koveshnikov, A.; Bylinskii, I.; Hodgson, G.; Yosifov, D.

    2014-01-01

    TRIUMF is involved in a major upgrade. The Advanced Rare IsotopeE Laboratory (ARIEL) has become a fully funded project in July 2010. A 10 mA 50 MeV SRF electron linac (e-linac) operating CW at 1.3 GHz is the key component of this initiative. This machine will serve as a second independent photo-fission driver for Rare Isotope Beams (RIB) production at TRIUMF's Isotope Separator and Accelerator (ISAC) facility. The cryogens delivery system requirements are driven by the electron accelerator cryomodule design [1, 2]. Since commencement of the project in 2010 the cryogenic system of e-linac has moved from the conceptual design phase into engineering design and procurement stage. The present document summarizes the progress in cryogenic system development and construction. Current status of e-linac cryogenic system including details of LN 2 storage and delivery systems, and helium subatmospheric (SA) system is presented. The first phase of e-linac consisting of two cryomodules, cryogens storage, delivery, and distribution systems, and a 600 W class liquid helium cryoplant is scheduled for installation and commissioning by year 2014

  13. Progress update on cryogenic system for ARIEL E-linac at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Koveshnikov, A.; Bylinskii, I.; Hodgson, G.; Yosifov, D. [TRIUMF, Vancouver, BC, V6T 2A3 (Canada)

    2014-01-29

    TRIUMF is involved in a major upgrade. The Advanced Rare IsotopeE Laboratory (ARIEL) has become a fully funded project in July 2010. A 10 mA 50 MeV SRF electron linac (e-linac) operating CW at 1.3 GHz is the key component of this initiative. This machine will serve as a second independent photo-fission driver for Rare Isotope Beams (RIB) production at TRIUMF's Isotope Separator and Accelerator (ISAC) facility. The cryogens delivery system requirements are driven by the electron accelerator cryomodule design [1, 2]. Since commencement of the project in 2010 the cryogenic system of e-linac has moved from the conceptual design phase into engineering design and procurement stage. The present document summarizes the progress in cryogenic system development and construction. Current status of e-linac cryogenic system including details of LN{sub 2} storage and delivery systems, and helium subatmospheric (SA) system is presented. The first phase of e-linac consisting of two cryomodules, cryogens storage, delivery, and distribution systems, and a 600 W class liquid helium cryoplant is scheduled for installation and commissioning by year 2014.

  14. Cryogenic cooler thermal coupler

    International Nuclear Information System (INIS)

    Green, K.E.; Talbourdet, J.A.

    1984-01-01

    A thermal coupler assembly mounted to the coldfinger of a cryogenic cooler which provides improved thermal transfer between the coldfinger and the detector assembly mounted on the dewar endwell. The thermal coupler design comprises a stud and spring-loaded cap mounted on the coldfinger assembly. Thermal transfer is made primarily through the air space between the cap and coldwell walls along the radial surfaces. The cap is spring loaded to provide thermal contact between the cap and endwell end surfaces

  15. Cryogenic high current discharges

    International Nuclear Information System (INIS)

    Meierovich, B.E.

    1994-01-01

    Z-pinches formed from frozen deuterium fibers by a rapidly rising current have enhanced stability and high neutron yield. The efforts to understand the enhanced stability and neutron yield on the basis of classical picture of Bennett equilibrium of the current channel has not given satisfactory results. The traditional approach does not take into account the essential difference between the frozen deuterium fiber Z-pinches and the usual Z-pinches such as exploding wires or classical gas-puffed Z-pinches. The very low temperature of the fiber atoms (10 K), together with the rapidly rising current, result in the coexistence of a high current channel with unionized fiber atoms for a substantial period of time. This phenomena lasts during the risetime. This approach takes into account the difference of the breakdown in a dielectric deuterium fiber and the breakdown in a metallic wire. This difference is essential to the understanding of specific features of cryogenic high current discharges. Z-pinches in frozen deuterium fibers should be considered as a qualitatively new phenomenon on the boundary of cryogenic and high current physics. It is a start of a new branch in plasma physics: the physics of cryogenic high current discharges

  16. Process instrumentation and control for cryogenic system of VECC

    International Nuclear Information System (INIS)

    Pal, Sandip

    2017-01-01

    Superconducting Cyclotron, which comprises of superconducting main magnet and cryopanels operating at 4.3 K, are operational at VECC in three phases starting from 2005; finally without interruption from July, 2010 to November, 2016. Cryogenic loads of the Cyclotron are catered by any of the two helium liquefiers/refrigerators (250W and 415W @ 4.5K) and associated cryogen distribution system with extensive helium gas management system. The system also consists of 31 K liters of liquid Nitrogen (LN_2) storage and delivery system, necessary of radiation shield. EPICS (Experimental Physics and Industrial Control System) architecture is open source, flexible and has unlimited tags as compared to the commercial Supervisory control and data acquisition (SCADA) packages. Hence, it has been adopted to design the SCADA module. The EPICS Input Output Controller (IOC) communicates with four PLCs over Ethernet based control LAN to control/monitor 618 numbers of field Inputs/ Outputs (I/O). The control system is fully automated and does not require any human intervention for routine operation. Since these two liquefiers share the same high pressure (HP) and low pressure (LP) pipelines, any pressure fluctuation due to rapid change in flow sometimes causes trip of the liquefiers. Few modifications are made in the control scheme in HP and LP zones to avoid liquefier trip. The plant is running very reliably round the clock and the historical data of important parameters during plant operation are archived for plant maintenance, easy diagnosis and future modifications. Total pure helium cycle gas inventory is monitored through EPICS for early detection of helium loss from its trend

  17. Limitations of superfluid helium droplets as host system revealed by electronic spectroscopy of embedded molecules

    Energy Technology Data Exchange (ETDEWEB)

    Premke, Tobias

    2016-02-19

    Superfluid helium nanodroplets serve a unique cryogenic host system ideal to prepare cold molecules and clusters. Structures as well as dynamic processes can be examined by means of high resolution spectroscopy. Dopant spectra are accompanied by helium-induced spectroscopic features which reveal information on the dopant to helium interaction. For this reason the experimental research focuses on the investigation of such helium-induced effects in order to provide new information on the microsolvation inside the droplets. Since the quantitative understanding of helium-induced spectral features is essential to interpret molecular spectra recorded in helium droplets, this study contributes further experimental details on microsolvation in superfluid helium droplets. For this purpose two contrary systems were examined by means of high resolution electronic spectroscopy. The first one, phthalocyanine (Pc), is a planar organic molecule offering a huge and planar surface to the helium atoms and thus, the non-superfluid helium solvation layer can form different structures. The second system is iodine and in contrast to Pc it is of simple molecular shape. That means that in this case different complex structures of the non-superfluid helium solvation layer and the dopant can be expected to be avoided. Thus, both molecules should show clear differences in their microsolvation behavior. In this work a detailed examination of different spectroscopic properties of phthalocyanine is given by means of fluorescence excitation and dispersed emission spectroscopy. It raises legitimate doubts about the assignment of experimentally observed signals to features predicted by the model of the microsolvation. Even though there are no experimental observations which disprove the empirical model for the solvation in helium droplets, an unambiguous assignment of the helium-induced spectroscopic structures is often not possible. In the second part of this work, the investigation of the

  18. Cryogenics in nuclear reactor technology

    International Nuclear Information System (INIS)

    Dharmadurai, G.

    1982-01-01

    The cryogenic technology has significantly contributed to the development of several proven techniques for use in the nuclear power industry. A noteworthy feature is the unique role of cryogenics in minimising the release of radioactive and some chemical pollutants to the environment during the operation of various plants associated with this industry. The salient technological features of several cryogenic processes relevant to the nuclear reactor technology are discussed. (author)

  19. Surface Tension Confines Cryogenic Liquid

    Science.gov (United States)

    Castles, Stephen H.; Schein, Michael E.

    1989-01-01

    New type of Dewar provides passive, constant-temperature cryogenic cooling for scientific instruments under normal-to low-gravity conditions. Known as Surface-Tension-Contained Liquid Cryogen Cooler (STCLCC), keeps liquid cryogen in known location inside the Dewar by trapping liquid inside spongelike material. Unique sponge material fills most of volume of inner tank. Sponge is all-silica, open-cell material similar to that used for Space Shuttle thermal-protection tiles.

  20. Modeling Results For the ITER Cryogenic Fore Pump. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Pfotenhauer, John M. [University of Wisconsin, Madison, WI (United States); Zhang, Dongsheng [University of Wisconsin, Madison, WI (United States)

    2014-03-31

    A numerical model characterizing the operation of a cryogenic fore-pump (CFP) for ITER has been developed at the University of Wisconsin – Madison during the period from March 15, 2011 through June 30, 2014. The purpose of the ITER-CFP is to separate hydrogen isotopes from helium gas, both making up the exhaust components from the ITER reactor. The model explicitly determines the amount of hydrogen that is captured by the supercritical-helium-cooled pump as a function of the inlet temperature of the supercritical helium, its flow rate, and the inlet conditions of the hydrogen gas flow. Furthermore the model computes the location and amount of hydrogen captured in the pump as a function of time. Throughout the model’s development, and as a calibration check for its results, it has been extensively compared with the measurements of a CFP prototype tested at Oak Ridge National Lab. The results of the model demonstrate that the quantity of captured hydrogen is very sensitive to the inlet temperature of the helium coolant on the outside of the cryopump. Furthermore, the model can be utilized to refine those tests, and suggests methods that could be incorporated in the testing to enhance the usefulness of the measured data.

  1. Cryogenic system for production testing and measurement of Fermilab energy saver superconducting magnets

    International Nuclear Information System (INIS)

    Cooper, W.E.; Bianchi, A.J.; Barger, R.K.; Johnson, F.B.; McGuire, K.J.; Pinyan, K.D.; Wilson, F.R.

    1983-03-01

    The cryogenic system of the Fermilab Magnet Test Facility has been used to provide cooling for the testing of approximately 1200 Energy Saver superconducting magnets. The system provides liquid helium, liquid nitrogen, gas purification, and vacuum support for six magnet test stands. It provides for simultaneous high current testing of two superconducting magnets and non-high current cold testing of two additional magnets. The cryogenic system has been in operation for about 32000 hours. The 1200 magnets have taken slightly more than three years to test

  2. A cryogenic system for TIBER II [Tokamak Ignition/Burn Experimental Reactor

    International Nuclear Information System (INIS)

    Slack, D.S.; Kerns, J.A.

    1987-01-01

    Phase II of the Tokamak Ignition/Burn Experimental Reactor (TIBER II) study describes one option for a small, economical, next-generation tokamak [1,2]. Because of its small size, minimum shielding is used between the plasma and the toroidal-field (TF) coils. Consequently, a large cryogenic system (approximately 70 kW at 4.5 K) capable of delivering forced-flow helium is required. This paper describes a cryogenic system that meets this requirement and includes TIBER-II requirements. 3 refs

  3. Use of microstructure control to toughen ferritic steels for cryogenic use. I. Fe--Ni steels

    International Nuclear Information System (INIS)

    Syn, C.K.; Jin, S.; Morris, J.W. Jr.

    1976-12-01

    Alternation of austenitization and austenite + ferrite two-phase decomposition treatment in a cyclic thermal treatment allows the achievement of ultra-fine grain size in steels containing 8-12% Ni. The grain refinement leads to a substantial improvement in cryogenic mechanical properties. The ductile-brittle transition temperature of a ferritic Fe-12Ni-0.25Ti alloy was suppressed to below liquid helium temperature by this grain refinement procedure; the transition temperature of commercial ''9Ni'' cryogenic steel was similarly reduced by combining the grain refinement with a final temper which introduces a small admixture of retained austenite

  4. Cryogenic system for production testing and measurement of Fermilab energy saver superconducting magnets

    International Nuclear Information System (INIS)

    Cooper, W.E.; Barger, R.K.; Bianchi, A.J.; Cooper, W.E.; Johnson, F.B.; McGuire, K.J.; Pinyan, K.D.; Wilson, F.R.

    1983-01-01

    The cryogenic system of the Fermilab Magnet Test Facility has been used to provide cooling for the testing of approximately 1200 Energy Saver superconducting magnets. The system provides liquid helium, liquid nitrogen, gas purification, and vacuum support for six magnet test stands. It provides for simultaneous high current testing of two superconducting magnets and nonhigh current cold testing of two additional magnets. The cryogenic system has been in operation for about 32000 hours. The 1200 magnets have taken slightly more than three years to test

  5. Cryogenic beam loss monitoring for the LHC

    International Nuclear Information System (INIS)

    Kurfürst, C.

    2013-01-01

    A Beam Loss Monitoring (BLM) system was installed on the outside surface of the LHC magnet cryostats to protect the accelerator equipment from beam losses. The protection is achieved by extracting the beam from the ring in case thresholds imposed on measured radiation levels are exceeded. Close to the interaction regions of the LHC, the present BLM system is sensitive to particle showers generated in the interaction region of the two beams. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and possible quench-provoking beam losses from the primary proton beams will be challenging. The particle showers measured by the present BLM configuration are partly shielded by the cryostat and the iron yoke of the magnets. The system can hence be optimised by locating beam loss monitors as close as possible to the protected element, i. e. the superconducting coils, inside the cold mass of the magnets in superfluid helium at 1.9 K. The advantage is that the dose measured by the Cryogenic Beam Loss Monitor (CryoBLM) would more precisely correspond to the dose deposited in the superconducting coil. The main challenges of this placement are the low temperature of 1.9 K and the integrated dose of 2 MGy in 20 years. Furthermore the CryoBLM should work in a magnetic field of 2 T and at a pressure of 1.1 bar, withstanding a fast pressure rise up to 20 bar in case of a magnet quench. The detector response should be linear between 0.1 and 10 mGy/s and faster than 1 ms. Once the detectors are installed in the LHC magnets, no access will be possible. Hence the detectors need to be available, reliable and stable for 20 years. Following intense research it became clear that no existing technology was proven to work in such conditions. The candidates under investigation in this work are diamond and silicon detectors and an ionisation chamber, using the liquid helium itself as particle detection medium

  6. A Focus on Cryogenic Engineering for the Primordial Inflation Polarization Explorer (PIPER) Mission

    Science.gov (United States)

    Rosas, Rogelio; Weston, Amy

    2011-01-01

    Cryogenic engineering involves design and modification of equipment that is used under boiling point of nitrogen which is 77 K. The focus of this paper will be on the design of hardware for cryogenic use and a retrofit that was done to the main laboratory cryostat used to test flight components for the Primordial Inflation Polarization Explorer balloon-borne mission. Data from prior tests showed that there was a superfluid helium leak and a total disassemble of the cryostat was conducted in order to localize and fix the leak. To improve efficiency new fill tubes and clamps with modifications were added to the helium tank. Upon removal of the tank, corrosion was found on the flange face that connects to the helium cold plate and therefore had to be fully replaced and copper plated to prevent future corrosion. Indium seals were also replaced for the four fill tubes, a helium level sensor, and the nitrogen and helium tanks. Four additional shielded twisted pairs of cryogenic wire and a wire harness for the Superconducting Quantum Interference Devices (SQUIDs) were added. Finally, there was also design work done for multiple pieces that went inside the cryostat and a separate probe used to test the SQUIDs. Upon successful completion of the cryostat upgrade, tests were run to check the effectiveness and stability of the upgrades. The post-retrofit tests showed minor leaks were still present and due to this, superfluidity has still not been attained. As such there could still be a possibility of a superfluid leak appearing in the future. Regardless, the copper plating on the helium tank has elongated the need to service it by three to five years.

  7. Design of the advanced divertor pump cryogenic system for DIII-D

    International Nuclear Information System (INIS)

    Schaubel, K.M.; Baxi, C.B.; Campbell, G.L.; Gootgeld, A.M.; Langhorn, A.R.; Laughon, G.J.; Smith, J.P.; Anderson, P.M.; Menon, M.M.

    1991-11-01

    The design of the cryogenic system for the D3-D advanced divertor cryocondensation pump is presented. The advanced divertor incorporates a baffle chamber and bias ring located near the bottom of the D3-D vacuum vessel. A 50,000 l/s cryocondensation pump will be installed underneath the baffle for plasma particle exhaust. The pump consists of a liquid helium cooled tube operating at 4.3 degrees K and a liquid nitrogen cooled radiation shield. Liquid helium is fed by forced flow through the cryopump. Compressed helium gas flowing through the high pressure side of a heat exchanger is regeneratively cooled by the two-phase helium leaving the pump. The cooled high pressure gaseous helium is than liquefied by a Joule-Thomson expansion valve. The liquid is returned to a storage dewar. The liquid nitrogen for the radiation shield is supplied by forced flow from a bulk storage system. Control of the cryogenic system is accomplished by a programmable logic controller

  8. Cryogenic equipment; Materiel cryogenique

    Energy Technology Data Exchange (ETDEWEB)

    Leger, L; Javellaud, J; Caro, C; Gilguy, R; Testard, O

    1966-06-01

    The cryostats presented here were built from standard parts; this makes it possible to construct a great variety of apparatus at minimum cost. The liquid nitrogen and helium reservoirs were designed so as to reduce losses to a minimum, and so as to make the cryostats as autonomous as possible. The experimental enclosure which is generally placed in the lower part of the apparatus requires a separate study in every case. Furthermore, complete assemblies such as transfer rods, isolated traps and high vacuum valves, were designed with a similar regard for the economic aspects and for the need for standardization. This equipment thus satisfies a great variety of experimental needs; it is readily adaptable and the consumptions of helium and liquid nitrogen are very low. (authors) [French] De nombreuses experiences utilisant les basses temperatures, necessitent l'emploi d'un materiel cryogenique complexe n'existant pas dans le commerce. Les cryostats presentes ici ont ete realises a partir d'elements standard, ce qui permet, malgre la diversite des appareils, de realiser un ensemble a moindre frais. Les reservoirs d'azote et d'helium liquides ont ete concus de facon a limiter les pertes et a conferer au cryostat la plus grande autonomie possible. L'enceinte experimentale situee en general dans la partie inferieure de l'appareil necessite dans tous les cas une etude speciale. D'autre part des ensembles complets tels que les cannes de transfert, piege isole, robinet pour vide secondaire, ont ete concus dans le meme souci de rentabilite et de standardisation. Ce materiel peut donc repondre a un grand nombre d'exigences experimentales, il est facilement adaptable, et les consommations d'helium et d'azote liquide sont tres reduites. (auteurs)

  9. Performance evaluation of cryogenic counter-flow heat exchangers with longitudinal conduction, heat in-leak and property variations

    Science.gov (United States)

    Jiang, Q. F.; Zhuang, M.; Zhu, Z. G.; Y Zhang, Q.; Sheng, L. H.

    2017-12-01

    Counter-flow plate-fin heat exchangers are commonly utilized in cryogenic applications due to their high effectiveness and compact size. For cryogenic heat exchangers in helium liquefaction/refrigeration systems, conventional design theory is no longer applicable and they are usually sensitive to longitudinal heat conduction, heat in-leak from surroundings and variable fluid properties. Governing equations based on distributed parameter method are developed to evaluate performance deterioration caused by these effects. The numerical model could also be applied in many other recuperators with different structures and, hence, available experimental data are used to validate it. For a specific case of the multi-stream heat exchanger in the EAST helium refrigerator, quantitative effects of these heat losses are further discussed, in comparison with design results obtained by the common commercial software. The numerical model could be useful to evaluate and rate the heat exchanger performance under the actual cryogenic environment.

  10. Neutral helium beam probe

    Science.gov (United States)

    Karim, Rezwanul

    1999-10-01

    This article discusses the development of a code where diagnostic neutral helium beam can be used as a probe. The code solves numerically the evolution of the population densities of helium atoms at their several different energy levels as the beam propagates through the plasma. The collisional radiative model has been utilized in this numerical calculation. The spatial dependence of the metastable states of neutral helium atom, as obtained in this numerical analysis, offers a possible diagnostic tool for tokamak plasma. The spatial evolution for several hypothetical plasma conditions was tested. Simulation routines were also run with the plasma parameters (density and temperature profiles) similar to a shot in the Princeton beta experiment modified (PBX-M) tokamak and a shot in Tokamak Fusion Test Reactor tokamak. A comparison between the simulation result and the experimentally obtained data (for each of these two shots) is presented. A good correlation in such comparisons for a number of such shots can establish the accurateness and usefulness of this probe. The result can possibly be extended for other plasma machines and for various plasma conditions in those machines.

  11. Antiprotonic helium atomcules

    Directory of Open Access Journals (Sweden)

    Sauge Sébastien

    2012-10-01

    Full Text Available About 3% of antiprotons ( stopped in helium are long-lived with microsecond lifetimes, against picoseconds in all other materials. This unusual longevity has been ascribed to the trapping of on metastable bound states in He+ helium atom-molecules thus named atomcules. Apart from their unique dual structure investigated by laser spectroscopy – a near-circular quasi-classical Rydberg atom with l ~ n – 1 ~ 37 or a special diatomic molecule with a negatively charged nucleus in high rotational state with J = l – the chemical physics aspects of their interaction with other atoms or molecules constitute an interesting topic for molecular physics. While atomcules may resist to million collisions in helium, molecular contaminants such as H2 are likely to destroy them in a single one, down to very low temperatures. In the Born-Oppenheimer framework, we interpret the molecular interaction obtained by ab initio quantum chemical calculations in terms of classical reactive channels, with activation barriers accounting for the experiments carried out in He and H2. From classical trajectory Monte Carlo simulations, we show that the thermalization stage strongly quenches initial populations, thus reduced to a recovered 3 % trapping fraction. This work illustrates the pertinence of chemical physics concepts to the study of exotic processes involving antimatter. New insights into the physico-chemistry of cold interstellar radicals are anticipated.

  12. Application of JLab 12GeV helium refrigeration system for the FRIB accelerator at MSU

    International Nuclear Information System (INIS)

    Ganni, V.; Knudsen, P.; Arenius, D.; Casagrande, F.

    2014-01-01

    The planned approach to have a turnkey helium refrigeration system for the MSU-FRIB accelerator system, encompassing the design, fabrication, installation and commissioning of the 4.5-K refrigerator cold box(es), cold compression system, warm compression system, gas management, oil removal and utility/ancillary systems, was found to be cost prohibitive. Following JLab’s suggestion, MSU-FRIB accelerator management made a formal request to evaluate the applicability of the recently designed 12GeV JLab cryogenic system for this application. The following paper will outline the findings and the planned approach for the FRIB helium refrigeration system

  13. Low-Z internal target from a cryogenically cooled liquid microjet source

    Energy Technology Data Exchange (ETDEWEB)

    Kuehnel, M.; Petridis, N. [Institut fuer Kernphysik, J.W. Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany); Winters, D.F.A. [GSI, Planckstr. 1, 64291 (Germany); Physikalisches Institut, Ruprecht-Karls-Universitaet, Philosophenweg 12, 69120 Heidelberg (Germany); Popp, U. [GSI, Planckstr. 1, 64291 (Germany); Doerner, R. [Institut fuer Kernphysik, J.W. Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt a. M. (Germany); Stoehlker, Th. [GSI, Planckstr. 1, 64291 (Germany); Physikalisches Institut, Ruprecht-Karls-Universitaet, Philosophenweg 12, 69120 Heidelberg (Germany); Grisenti, R.E. [Institut fuer Kernphysik, J.W. Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany); GSI, Planckstr. 1, 64291 (Germany)], E-mail: grisenti@atom.uni-frankfurt.de

    2009-04-21

    We carried out an extensive investigation on the production of cryogenically cooled liquid hydrogen and helium droplet beams at the experimental storage ring at GSI with the goal to achieve high area densities for these low-Z internal targets. Our results show that an area density of up to 10{sup 14}cm{sup -2} is achieved for both light gases by expanding the liquid through sub-10 {mu}m diameter nozzles. The achieved area density is comparable with the previous results for the hydrogen internal target and represents an improvement by about four orders of magnitude for the helium target.

  14. Low-Z internal target from a cryogenically cooled liquid microjet source

    International Nuclear Information System (INIS)

    Kuehnel, M.; Petridis, N.; Winters, D.F.A.; Popp, U.; Doerner, R.; Stoehlker, Th.; Grisenti, R.E.

    2009-01-01

    We carried out an extensive investigation on the production of cryogenically cooled liquid hydrogen and helium droplet beams at the experimental storage ring at GSI with the goal to achieve high area densities for these low-Z internal targets. Our results show that an area density of up to 10 14 cm -2 is achieved for both light gases by expanding the liquid through sub-10 μm diameter nozzles. The achieved area density is comparable with the previous results for the hydrogen internal target and represents an improvement by about four orders of magnitude for the helium target.

  15. Testing of a cryogenic recooler heat exchanger at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Nicoletti, A.; Wu, K.C.

    1993-01-01

    Brookhaven National Laboratory has tested a recooler heat exchanger intended to be used in the cryogenic system of the Relativistic Heavy Ion Collider. The unit is required to transfer 225 Watts from a supercritical helium stream flowing at 100 g/s to a helium bath boiling at 4.25 K. Measurements made with heat loads of 50 to over 450 Watts on the unit indicate its cooling capacity is greater than 400 Watts, as expected, and it will be suitable for use in the RHIC ring. Presented are the modifications made to BNL's MAGCOOL test facility that were necessary for testing, test procedure, and recooler performance

  16. A confocal optical microscope for detection of single impurities in a bulk crystal at cryogenic temperatures.

    Science.gov (United States)

    Karlsson, Jenny; Rippe, Lars; Kröll, Stefan

    2016-03-01

    A compact sample-scanning confocal optical microscope for detection of single impurities below the surface of a bulk crystal at cryogenic temperatures is described. The sample, lens, and scanners are mounted inside a helium bath cryostat and have a footprint of only 19 × 19 mm. Wide field imaging and confocal imaging using a Blu-ray lens immersed in liquid helium are demonstrated with excitation at 370 nm. A spatial resolution of 300 nm and a detection efficiency of 1.6% were achieved.

  17. Leak-tightness assessment of demountable joints for the super fluid helium system of the CERN Large Hadron Collider (LHC)

    International Nuclear Information System (INIS)

    Brunet, J.C.; Poncet, A.; Trilhe, P.

    1994-01-01

    The future high energy accelerator LHC presently considered at CERN, will make heavy use of demountable cryogenic joints operating at superfluid helium temperatures (1.8 K). These joints will be required for connecting the cryomagnets to their feeding lines, helium safety valves to cold masses, both on their measuring benches and eventually in their final installation set-up. The very large size of the future machine and, consequently, the large number of cryogenic joints imply that their reliability in leak tightness be very high, in particular after extreme loading conditions such as the high helium pressures resulting from superconducting magnet quenches. For these reasons, a test set-up has been especially built at CERN to reproduce these conditions, and to assess the leak tightness reliability of commercially available joints. A description of the facility is presented, together with the first test results

  18. Helium turbomachinery operating experience from gas turbine power plants and test facilities

    International Nuclear Information System (INIS)

    McDonald, Colin F.

    2012-01-01

    The closed-cycle gas turbine, pioneered and deployed in Europe, is not well known in the USA. Since nuclear power plant studies currently being conducted in several countries involve the coupling of a high temperature gas-cooled nuclear reactor with a helium closed-cycle gas turbine power conversion system, the experience gained from operated helium turbomachinery is the focus of this paper. A study done as early as 1945 foresaw the use of a helium closed-cycle gas turbine coupled with a high temperature gas-cooled nuclear reactor, and some two decades later this was investigated but not implemented because of lack of technology readiness. However, the first practical use of helium as a gas turbine working fluid was recognized for cryogenic processes, and the first two small fossil-fired helium gas turbines to operate were in the USA for air liquefaction and nitrogen production facilities. In the 1970's a larger helium gas turbine plant and helium test facilities were built and operated in Germany to establish technology bases for a projected future high efficiency large nuclear gas turbine power plant concept. This review paper covers the experience gained, and the lessons learned from the operation of helium gas turbine plants and related test facilities, and puts these into perspective since over three decades have passed since they were deployed. An understanding of the many unexpected events encountered, and how the problems, some of them serious, were resolved is important to avoid them being replicated in future helium turbomachines. The valuable lessons learned in the past, in many cases the hard way, particularly from the operation in Germany of the Oberhausen II 50 MWe helium gas turbine plant, and the technical know-how gained from the formidable HHV helium turbine test facility, are viewed as being germane in the context of current helium turbomachine design work being done for future high efficiency nuclear gas turbine plant concepts. - Highlights:

  19. Cryogenic implications for DT

    International Nuclear Information System (INIS)

    Souers, P.C.

    1977-10-01

    Cryogenic hydrogen data is being compiled for magnetic fusion engineering. Many physical properties of DT can be extrapolated from H 2 and D 2 values. The phase diagram properties of the D 2 -DT-T 2 mixture are being measured. Three properties which will be greatly affected by tritium should be measured. In order of their perceived importance, they are: (1) solid thermal conductivity, (2) solid mechanical strength, and (3) gaseous electrical conductivity. The most apparent need for DT data is in Tokomak fuel pellet injection. Cryopumping and distillation applications are also considered

  20. Kodak AMSD Cryogenic Test Plans

    Science.gov (United States)

    Matthews, Gary; Hammon, John; Barrett, David; Russell, Kevin (Technical Monitor)

    2002-01-01

    NGST will be an IR based optical system that will operate at cryogenic temperatures. As part of the AMSD program, Kodak must demonstrate the ability of our system to perform at these very cold temperatures. Kodak will discuss the test approach that will be used for cryogenic testing at MSFC's XRCF.

  1. Cryogenic forced convection refrigerating system

    International Nuclear Information System (INIS)

    Klee, D.J.

    1988-01-01

    This patent describes the method of refrigerating products by contact with a refrigerating gas which comprises introducing product into a refrigeration zone, contacting the product with the refrigerating gas for a sufficient time to refrigerate it to the appropriate extent and removing the refrigerated product. The improvement for producing the refrigeration gas from a liquid cryogen such that essentially all of the liquid cryogen is fully vaporized before contacting the product comprises: (a) introducing the liquid cryogen, selected from the group consisting of liquid air and liquid nitrogen, at elevated pressure into an ejector as the motive fluid to accelerate a portion of a warm refrigerating gas through the ejector while mixing the cryogen and gas to effect complete vaporization of the liquid cryogen and substantial cooling of the portion of the refrigerating gas resulting in a cold discharge gas which is above the liquefaction temperature of the cryogen; (b) introducing the cold discharge gas into a forced circulation pathway of refrigerating gas and producing a cold refrigerating gas which contacts and refrigerates product and is then at least partially recirculated; (c) sensing the temperature of the refrigerating gas in the forced circulation pathway and controlling the introduction of liquid cryogen with regard to the sensed temperature to maintain the temperature of the discharge gas above the liquefacton temperature of the cryogen utilized

  2. Surface electrons of helium films

    International Nuclear Information System (INIS)

    Studart, N.; Hipolito, O.

    1986-01-01

    Theoretical calculations of some properties of two-dimensional electrons on a liquid helium film adsorbed on a solid substrate are reviewed. We describe the spectrum of electron bound states on bulk helium as well on helium films. The correlational properties, such as the structure factor and correlation energy, are determined as functions of the film thickness for different types of substrates in the framework of a Generalized Random-Phase Approximation. The collective excitations of this system are also described. The results for electrons on the surface of thin films and bulk helium are easily obtained. we examine the electron interaction with the excitations of the liquid helium surface resulting in a new polaron state, which was observed very recently. The ground state energy and the effective mass of this polaron are determined by using the path-integral formalism and unitary-transformation method. Recent speculations about the phase diagram of electrons on the helium film are also discussed. (Author) [pt

  3. Verification test for helium panel of cryopump for DIII-D advanced divertor

    International Nuclear Information System (INIS)

    Baxi, C.B.; Laughon, G.J.; Langhorn, A.R.; Schaubel, K.M.; Smith, J.P.; Gootgeld, A.M.; Campbell, G.L.; Menon, M.M.

    1992-01-01

    It is planned to install a cryogenic pump in the lower divertor portion of the DIII-D tokamak with a pumping speed of 50000 ell/s and an exhaust of 2670 Pa-ell/s (20 Torr-ell/s). A coaxial counter flow configuration has been chosen for the helium panel of this cryogenic pump. This paper evaluates cool-down rates and fluid stability of this configuration. A prototypic test was performed at General Atomics (GA) to increase confidence in the design. It was concluded that the helium panel cooldown rate agreed quite well with analytical prediction and was within acceptable limits. The design flow rate proved stable and two-phase pressure drop can be predicted quite accurately

  4. Verification test for helium panel of cryopump for DIII-D advanced divertor

    International Nuclear Information System (INIS)

    Baxi, C.B.; Laughon, G.J.; Langhorn, A.R.; Schaubel, K.M.; Smith, J.P.; Gootgeld, A.M.; Campbell, G.L.; Menon, M.M.

    1991-10-01

    It is planned to install a cryogenic pump in the lower divertor portion of the D3-D tokamak with a pumping speed of 50000 ell/s and an exhaust of 2670 Pa-ell/s (20 Torr-ell s). A coaxial counter flow configuration has been chosen for the helium panel of this cryogenic pump. This paper evaluates cooldown rates and fluid stability of this configuration. A prototypic test was performed at General Atomics (GA) to increase confidence in the design. It was concluded that the helium panel cooldown rate agreed quite well with analytical prediction and was within acceptable limits. The design flow rate proved stable and two-phase pressure drop can be predicted quite accurately. 8 refs., 5 figs., 1 tab

  5. Light induced cooling of a heated solid immersed in liquid helium I

    International Nuclear Information System (INIS)

    Lezak, D.; Brodie, L.C.; Semura, J.S.

    1984-01-01

    This chapter investigates the marked enhancement in the transient heat transfer from the heater-thermometer to the liquid helium immediately following the application of a flash of visible light. This ''light effect'' is associated with increased bubble activity, and it is possible that the light induces a rapid nucleation of bubbles in the superheated liquid at or near the heater surface. A summary of the light effect is presented and some potential uses to which this effect could be applied are suggested. Quantification of the light effect and properties of the light effect are discussed. It is determined that the light effect is an additional cooling due to a light induced enhancement of boiling in superheated liquid helium I. The effect could be applied in practical cryogenic engineering and for the acquisition of fundamental knowledge of boiling heat transfer and nucleation in cryogenic liquids

  6. Cryogenic and thermal design for the Space Infrared Telescope Facility (SIRTF)

    Science.gov (United States)

    Lee, J. H.; Brooks, W. F.

    1984-01-01

    The 1-meter class cryogenically cooled Space Infrared Telescope Facility (SIRTF) planned by NASA, is scheduled for a 1992 launch. SIRTF would be deployed from the Shuttle, and placed into a sun synchronous polar orbit of 700 km. The facility has been defined for a mission with a minimum initial lifetime of one year in orbit with mission extension that could be made possible through in-orbit servicing of the superfluid helium cryogenic system, and use of a thermal control system. The superfluid dewar would use an orbital disconnect system for the tank supports, and vapor cooling of the barrel baffle. The transient analysis of the design shows that the superfluid helium tank with no active feedback comes within temperature requirements for the nominal orbital aperture heat load, quiescent instrument, and chopper conditions.

  7. Manufacturing and Installation of the Compound Cryogenic Distribution Line for the Large Hadron Collider

    CERN Document Server

    Riddone,, G; Bouillot, A; Brodzinski, K; Dupont, M; Fathallah, M; Fournel, JL; Gitton, E; Junker, S; Moussavi, H; Parente, C; Riddone, G

    2007-01-01

    The Large Hadron Collider (LHC) [1] currently under construction at CERN will make use of superconducting magnets operating in superfluid helium below 2 K. A compound cryogenic distribution line (QRL) will feed with helium at different temperatures and pressures the local elementary cooling loops in the cryomagnet strings. Low heat inleak to all temperature levels is essential for the overall LHC cryogenic performance. Following a competitive tendering, CERN adjudicated in 2001 the contract for the series line to Air Liquide (France). This paper recalls the main features of the technical specification and shows the project status. The basic choices and achievements for the industrialization phase of the series production are also presented, as well as the installation issues and status.

  8. Overview of different control strategies for a typical cryogenic warm compressor station at CERN

    Science.gov (United States)

    Pezzetti, M.; Garcia, C. V. M.; Bradu, B.; Rogez, E.

    2017-12-01

    Helium cryogenic systems are extensively used at CERN under several configurations for accelerators and detectors. The Warm Compressor Station (WCS) is the primary component of the helium cryogenic systems. The basic controls structure mainly depends on the bypass, charge and discharge valves configuration ensuring the nominal flow and compression ratio. This paper presents three studied methods for the WCS process control systems covering all transient and operational requirements: the proportional-integral-derivative (PID) control approach, the Fuzzy Logic Control approach (FLC) and the Internal Model Control approach (IMC). The paper emphasizes on simulation results of the different control strategies using Ecosimpro software associated to the CERN CryoLib library. Advantages and limitations of each method are presented.

  9. Canada's helium output rising fast

    Energy Technology Data Exchange (ETDEWEB)

    1966-12-01

    About 12 months from now, International Helium Limited will be almost ready to start up Canada's second helium extraction plant at Mankota, in Saskatchewan's Wood Mountain area about 100 miles southwest of Moose Jaw. Another 80 miles north is Saskatchewan's (and Canada's) first helium plant, operated by Canadian Helium and sitting on a gas deposit at Wilhelm, 9 miles north of Swift Current. It contains almost 2% helium, some COD2U, and the rest nitrogen. One year in production was apparently enough to convince Canadian Helium that the export market (it sells most of its helium in W. Europe) can take a lot more than it's getting. Construction began this summer on an addition to the Swift Current plant that will raise its capacity from 12 to 36MMcf per yr when it goes on stream next spring. Six months later, International Helium's 40 MMcf per yr plant to be located about 4 miles from its 2 Wood Mountain wells will double Canada's helium output again.

  10. A Simulation Study for the Virtual Commissioning of the CERN Central Helium Liquefier

    CERN Document Server

    Rogez, E; Moraux, A; Pezzetti, M; Gayet, P; Coppier, H

    2009-01-01

    This paper describes the implication of dynamic simulation in cryogenics processes. The simulation aims to prepare plant commissioning and operation, and to validate the efficiency of the new process control logic. PLC programs have been tested on a process simulator integrating physical models of valves, heat exchangers, turbines, phase separator, and helium data. The model has shown the capacity to reproduce cold-box dynamic behaviour, from 300 K to 4.5 K.

  11. Mirror fusion test facility cryogenic system - performance, management approach, and present equipment status

    International Nuclear Information System (INIS)

    Slack, D.S.; Chronis, W.C.

    1988-01-01

    The cryogenic system for the MFTF is a helium refrigeration system that proved to be successful and cost effective. All operating objectives were met while remaining within a few percent of the initial cost and schedule plans. The management approach used at MFTF is assessed. Manpower levels, extent and type of industrial participation, and subcontractor specifications and interactions are reviewed along with highlights of system testing, documentation, and operation

  12. Low flow velocity, fine-screen heat exchangers and vapor-cooled cryogenic current leads

    International Nuclear Information System (INIS)

    Steyert, W.A.; Stone, N.J.

    1978-09-01

    The design, construction, and testing of three compact, low temperature heat exchangers are reported. A method is given for the construction of a small (approximately = 20-cm 3 volume) exchanger that can handle 6 g/s helium flow with low pressure drops (ΔP/P = 10 percent) and adequate heat transfer (N/sub tu/ = 3). The use of screen for simple, vapor-cooled current leads into cryogenic systems is also discussed

  13. Orion A helium abundance

    International Nuclear Information System (INIS)

    Tsivilev, A.P.; Ershov, A.A.; Smirnov, G.T.; Sorochenko, R.L.

    1986-01-01

    The 22.4-GHz (H,He)66-alpha and 36.5-GHz (H,He)56-alpha radio recombination lines have been observed at several Jaffe-Pankonin positions in the central part of the Orion A source. The measured relative abundance of ionized helium increases with distance, averaging 11.6 percent at peripheral points. The observed behavior is interpreted by a blister-type model nebula, which implies that Orion A has a true He abundance of 12 percent, is moving with a radial velocity of 5 km/sec, and is expanding. 18 references

  14. Simulation of liquid helium

    International Nuclear Information System (INIS)

    Ceperley, D.M.

    1985-07-01

    The author discusses simulation methods for quantum mechanical systems at finite temperatures. Recently it has been shown that static properties of some quantum systems can be obtained by simulation in a straightforward manner using path integrals, albeit with an order of magnitude more computing effort needed than for the corresponding classical systems. Some dynamical information can be gleaned from these simulations as will be discussed below. But this is very limited - there is no quantum version of the molecular dynamics method. The path integral method is illustrated by discussing the application to liquid helium. 12 refs., 8 figs

  15. The Fast Alternative Cryogenic Experiment Testbed

    Science.gov (United States)

    Nash, Alfred; Holmes, Warren

    2000-01-01

    One of the challenges in the area of cryogenics for space exploration in the next millennium is providing the capability for inexpensive, frequent, access to space. Faced with this challenge during the International Space Station (ISS) build era, when other Space Shuttle manifesting opportunities are unavailable, a "proof of concept" cryostat has been developed to demonstrate the ability to accommodate low temperature science investigations within the constraints of the Hitchhiker siderail carrier. The Hitchhiker siderail carrier is available on a "mass available" basis during the ISS build era. In fact, several hitchhiker payloads flew with the deployment of the Unity module. Hitchhiker siderail carrier payloads have historically flown an average of about four times a year. A hybrid Solid Neon - Superfluid Helium cryostat has been developed with Janis Research Company to accommodate instruments of 16.5 cm diameter and 30 cm. length. This hybrid approach was taken in part to provide adequate on-orbit lifetime for instruments with high (conducted) heat loads from the instrumentation wiring. Mass, volume, lifetime and the launch hold scenario were all design drivers. In addition, with Ball Aerospace and Technologies Corporation, a multichannel VME architecture Germanium Resistance Thermometer (GRT) readout and heater control servo system has been developed. In a flight system, the cryostat and electronics payloads would be umbilically attached in a paired Hitchhiker siderail mount, and permit on-orbit command and telemetry capability. The results of performance tests of both the cryostat, and a helium sample instrument will be presented. The instrument features a self contained, miniaturized, nano-Kelvin resolution High Resolution Thermometer (HRT). This high level of thermal resolution is achieved through the utilization of a dc Superconducting Quantum Interference Device (SQUID). Although developed for the Low Temperature Microgravity Fundamental Physics

  16. Cryogenic test of the equivalence principle

    International Nuclear Information System (INIS)

    Worden, P.W. Jr.

    1976-01-01

    The weak equivalence principle is the hypothesis that the ratio of internal and passive gravitational mass is the same for all bodies. A greatly improved test of this principle is possible in an orbiting satellite. The most promising experiments for an orbital test are adaptations of the Galilean free-fall experiment and the Eotvos balance. Sensitivity to gravity gradient noise, both from the earth and from the spacecraft, defines a limit to the sensitivity in each case. This limit is generally much worse for an Eotvos balance than for a properly designed free-fall experiment. The difference is related to the difficulty of making a balance sufficiently isoinertial. Cryogenic technology is desirable to take full advantage of the potential sensitivity, but tides in the liquid helium refrigerant may produce a gravity gradient that seriously degrades the ultimate sensitivity. The Eotvos balance appears to have a limiting sensitivity to relative difference of rate of fall of about 2 x 10 -14 in orbit. The free-fall experiment is limited by helium tide to about 10 -15 ; if the tide can be controlled or eliminated the limit may approach 10 -18 . Other limitations to equivalence principle experiments are discussed. An experimental test of some of the concepts involved in the orbital free-fall experiment is continuing. The experiment consists in comparing the motions of test masses levitated in a superconducting magnetic bearing, and is itself a sensitive test of the equivalence principle. At present the levitation magnets, position monitors and control coils have been tested and major noise sources identified. A measurement of the equivalence principle is postponed pending development of a system for digitizing data. The experiment and preliminary results are described

  17. Cryogenic Preamplifiers for Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Johansen, Daniel H.; Sanchez-Heredia, Juan D.; Petersen, Jan R.

    2018-01-01

    Pursuing the ultimate limit of detection in magnetic resonance imaging (MRI) requires cryogenics to decrease the thermal noise of the electronic circuits. As cryogenic coils for MRI are slowly emerging cryogenic preamplifiers are required to fully exploit their potential. A cryogenic preamplifier...

  18. Investigation of two and three parameter equations of state for cryogenic fluids

    International Nuclear Information System (INIS)

    Jenkins, S.L.; Majumdar, A.K.; Hendricks, R.C.

    1990-01-01

    Two-phase flows are a common occurrence in cryogenic engines and an accurate evaluation of the heat-transfer coefficient in two-phase flow is of significant importance in their analysis and design. The thermodynamic equation of state plays a key role in calculating the heat transfer coefficient which is a function of thermodynamic and thermophysical properties. An investigation has been performed to study the performance of two- and three-parameter equations of state to calculate the compressibility factor of cryogenic fluids along the saturation loci. The two-parameter equations considered here are van der Waals and Redlich-Kwong equations of state. The three-parameter equation represented here is the generalized Benedict-Webb-Rubin (BWR) equation of Lee and Kesler. Results have been compared with the modified BWR equation of Bender and the extended BWR equations of Stewart. Seven cryogenic fluids have been tested; oxygen, hydrogen, helium, nitrogen, argon, neon, and air. The performance of the generalized BWR equation is poor for hydrogen and helium. The van der Waals equation is found to be inaccurate for air near the critical point. For helium, all three equations of state become inaccurate near the critical point. 13 refs

  19. High Efficiency Regenerative Helium Compressor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Helium plays several critical rolls in spacecraft propulsion. High pressure helium is commonly used to pressurize propellant fuel tanks. Helium cryocoolers can be...

  20. IMPROVEMENTS TO THE CRYOGENIC CONTROL SYSTEM ON DIII-D

    International Nuclear Information System (INIS)

    HOLTROP, K.L; ANDERSON, P.M; MAUZEY, P.S.

    2004-03-01

    OAK-B135 The cryogenic facility that is part of the DIII-D tokamak system supplies liquid nitrogen and liquid helium to the superconducting magnets used for electron cyclotron heating, the D 2 pellet injection system, cryopumps in the DIII-D vessel, and cryopanels in the neutral beam injection system. The liquid helium is liquefied on site using a Sulzer liquefier that has a 150 l/h liquefaction rate. Control of the cryogenic facility at DIII-D was initially accomplished through the use of three different programmable logic controllers (PLCs). Recently, two of those three PLCs, a Sattcon PLC controlling the Sulzer liquefier and a Westinghouse PLC, were removed and all their control logic was merged into the remaining PLC, a Siemens T1555. This replacement was originally undertaken because the removed PLCs were obsolete and unsupported. However, there have been additional benefits from the replacement. The replacement of the RS-232 serial links between the graphical user interface and the PLCs with a high speed Ethernet link allows for real-time display and historical trending of nearly all the cryosystem's data. this has greatly increased the ability to troubleshoot problems with the system, and has permitted optimization of the cryogenic system's performance because of the increased system integration. To move the control logic of the Sattcon control loops into the T1555, an extensive modification of the basic PID control was required. These modifications allow for better control of the control loops and are now being incorporated in other control loops in the system

  1. Upgrade of the cryogenic infrastructure of SM18, CERN main test facility for superconducting magnets and RF cavities

    Science.gov (United States)

    Perin, A.; Dhalla, F.; Gayet, P.; Serio, L.

    2017-12-01

    SM18 is CERN main facility for testing superconducting accelerator magnets and superconducting RF cavities. Its cryogenic infrastructure will have to be significantly upgraded in the coming years, starting in 2019, to meet the testing requirements for the LHC High Luminosity project and for the R&D program for superconducting magnets and RF equipment until 2023 and beyond. This article presents the assessment of the cryogenic needs based on the foreseen test program and on past testing experience. The current configuration of the cryogenic infrastructure is presented and several possible upgrade scenarios are discussed. The chosen upgrade configuration is then described and the characteristics of the main newly required cryogenic equipment, in particular a new 35 g/s helium liquefier, are presented. The upgrade implementation strategy and plan to meet the required schedule are then described.

  2. A cryogenic test stand for full length SSC magnets with superfluid capability

    International Nuclear Information System (INIS)

    Peterson, T.J.; Mazur, P.O.

    1989-02-01

    The Fermilab Magnet Test Facility performs testing of the full scale SSC magnets on test stands capable of simulating the cryogenic environment of the SSC main ring. One of these test stands, Stand 5, also has the ability to operate the magnet under test at temperatures from 1.8K to 4.5K with either supercritical helium or subcooled liquid, providing at least 25 Watts of refrigeration. At least 50 g/s flow is available from 2.3K to 4.5K, whereas superfluid operation occurs with zero flow. Cooldown time from 4.5K to 1.8K is 1.5 hours. A maximum current capability of 10,000 amps is provided, as is instrumentation to monitor and control the cryogenic conditions. This paper describes the cryogenic design of this test stand. 8 refs., 6 figs

  3. Design and construction of the SSCL magnet test laboratory cryogenic systems

    International Nuclear Information System (INIS)

    Freeman, M.A.; Kobel, T.A.

    1992-01-01

    The intent of this document is to provide a brief summary of the execution, by Process Systems International, Inc. (PSI), of the Design and Construction of the SSCL Magnet Test Laboratory Cryogenic Systems. This $30 million project requires the expenditure of over 200,000 manhours and the procurement of $17 million in materials within a two year period. SSC magnets will be performance tested at the Magnet Test Laboratory (MTL) and the Accelerator System String Test (ASST) facility under conditions simulating the environment of the SSC main ring. The cryogenic system consists of test stands (five for MTL, one for ASST) and the associated equipment including cryogenic storage, purification, thermal conditioning, and helium refrigeration necessary to support the test program

  4. Cryogenic aluminum-wound generator rotor concept for nuclear power conversion

    International Nuclear Information System (INIS)

    Schlicher, R.L.; Oberly, C.E.

    1987-01-01

    This paper presents a design outline for a liquid hydrogen cooled generator rotor that could be used to fabricate a 20-megawatt cryogenic generator. The armature of an existing 20-megawatt superconducting generator could be utilized in this new cryogenic generator concept without electrical modification and with minimum modification to its housing. The acquisition and operating expense of liquid helium liquefiers, refrigeration requirements and the expense of fabricating a superconductor wound generator rotor make an aluminum-wound rotor a viable alternative. Ideally, the aluminum rotor could use the higher cryogenic temperatures of liquid hydrogen at 21 K as conductor coolant and not require the more difficult fabrication techniques of a superconducting generator rotor. A most likely conductor candidate is high purity aluminum which has 0.2% its room temperature resistance at liquid hydrogen temperatures. Recent research has indicated the feasibility of fabricating high-purity aluminum conductors in a composite conductor form

  5. Cryogenics for high-energy particle accelerators: highlights from the first fifty years

    CERN Document Server

    AUTHOR|(CDS)2067931

    2017-01-01

    Applied superconductivity has become a key technology for high-energy particle accelerators, allowing to reach higher beam energy while containing size, capital expenditure and operating costs. Large and powerful cryogenic systems are therefore ancillary to low-temperature superconducting accelerator devices – magnets and high-frequency cavities – distributed over multi-kilometre distances and operating generally close to the normal boiling point of helium, but also above 4.2 K in supercritical and down to below 2 K in superfluid. Additionally, low-temperature operation in accelerators may also be required by considerations of ultra-high vacuum, limited stored energy and beam stability. We discuss the rationale for cryogenics in high-energy particle accelerators, review its development over the past half-century and present its outlook in future large projects, with reference to the main engineering domains of cryostat design and heat loads, cooling schemes, efficient power refrigeration and cryogenic flu...

  6. Design and operating experience of the cryogenic system of the U.S. SCMS as incorporated into the bypass loop of the U-25 MHD generator facility

    International Nuclear Information System (INIS)

    Niemann, R.C.; Mataya, K.F.; McWilliams, D.A.; Borden, R.; Streeter, M.H.; Wickson, R.; Smelser, P.; Privalov, N.P.

    1978-01-01

    The design features and accumulated operating experience, from a cryogenics point of view, of the United States Superconducting Magnet System (U.S. SCMS) are presented. The principal cryogenic system design parameters are enumerated. Details of the cryogenic aspects of magnetic system commissioning, standby mode, and operation with MHD generators are discussed. Included are system operation, problems encountered and corrective actions taken, and measured operating parameters which include liquid helium boiloff, cryostat pressure and level versus time, etc. The aspects of the transition between operation in the laboratory and in an MHD plant are elaborated

  7. Helium production in reactor materials

    International Nuclear Information System (INIS)

    Lippincott, E.P.; McElroy, W.N.; Farrar, H. IV.

    1975-02-01

    Comparisons of integral helium production measurements with predictions based on ENDF/B Version IV cross sections have been made. It is concluded that an ENDF/B helium production cross section file should be established in order to ensure a complete and consistent cross section evaluation to meet accuracies required for LMFBR, CTR, and LWR applications. (U.S.)

  8. Helium behaviour in nuclear glasses

    International Nuclear Information System (INIS)

    Fares, T.

    2011-01-01

    The present thesis focuses on the study of helium behavior in R7T7 nuclear waste glass. Helium is generated by the minor actinides alpha decays incorporated in the glass matrix. Therefore, four types of materials were used in this work. These are non radioactive R7T7 glasses saturated with helium under pressure, glasses implanted with 3 He + ions, glasses doped with curium and glasses irradiated in nuclear reactor. The study of helium solubility in saturated R7T7 glass has shown that helium atoms are inserted in the glass free volume. The results yielded a solubility of about 10 16 at. cm -3 atm. -1 . The incorporation limit of helium in this type of glass has been determined; its value amounted to about 2*10 21 at. cm -3 , corresponding to 2.5 at.%. Diffusion studies have shown that the helium migration is controlled by the single population dissolved in the glass free volume. An ideal diffusion model was used to simulate the helium release data which allowed to determine diffusion coefficients obeying to the following Arrhenius law: D = D 0 exp(-E a /kBT), where D 0 = 2.2*10 -2 and 5.4*10 -3 cm 2 s -1 and E a = 0.61 eV for the helium saturated and the curium doped glass respectively. These results reflect a thermally activated diffusion mechanism which seems to be not influenced by the glass radiation damage and helium concentrations studied in the present work (up to 8*10 19 at. g -1 , corresponding to 0.1 at.%). Characterizations of the macroscopic, structural and microstructural properties of glasses irradiated in nuclear reactor did not reveal any impact associated with the presence of helium at high concentrations. The observed modifications i.e. a swelling of 0.7 %, a decrease in hardness by 38 %, an increase between 8 and 34 % of the fracture toughness and a stabilization of the glass structure under irradiation, were attributed to the glass nuclear damage induced by the irradiation in reactor. Characterizations by SEM and TEM of R7T7 glasses implanted

  9. Cryogenic Tracking Detectors

    CERN Multimedia

    Luukka, P R; Tuominen, E M; Mikuz, M

    2002-01-01

    The recent advances in Si and diamond detector technology give hope of a simple solution to the radiation hardness problem for vertex trackers at the LHC. In particular, we have recently demonstrated that operating a heavily irradiated Si detector at liquid nitrogen (LN$_2$) temperature results in significant recovery of Charge Collection Efficiency (CCE). Among other potential benefits of operation at cryogenic temperatures are the use of large low-resistivity wafers, simple processing, higher and faster electrical signal because of higher mobility and drift velocity of carriers, and lower noise of the readout circuit. A substantial reduction in sensor cost could result The first goal of the approved extension of the RD39 program is to demonstrate that irradiation at low temperature in situ during operation does not affect the results obtained so far by cooling detectors which were irradiated at room temperature. In particular we shall concentrate on processes and materials that could significantly reduce th...

  10. Cryogenic Cam Butterfly Valve

    Science.gov (United States)

    McCormack, Kenneth J. (Inventor)

    2016-01-01

    A cryogenic cam butterfly valve has a body that includes an axially extending fluid conduit formed there through. A disc lug is connected to a back side of a valve disc and has a circular bore that receives and is larger than a cam of a cam shaft. The valve disc is rotatable for a quarter turn within the body about a lug axis that is offset from the shaft axis. Actuating the cam shaft in the closing rotational direction first causes the camming side of the cam of the cam shaft to rotate the disc lug and the valve disc a quarter turn from the open position to the closed position. Further actuating causes the camming side of the cam shaft to translate the valve disc into sealed contact with the valve seat. Opening rotational direction of the cam shaft reverses these motions.

  11. Real-gas effects 1: Simulation of ideal gas flow by cryogenic nitrogen and other selected gases

    Science.gov (United States)

    Hall, R. M.

    1980-01-01

    The thermodynamic properties of nitrogen gas do not thermodynamically approximate an ideal, diatomic gas at cryogenic temperatures. Choice of a suitable equation of state to model its behavior is discussed and the equation of Beattie and Bridgeman is selected as best meeting the needs for cryogenic wind tunnel use. The real gas behavior of nitrogen gas is compared to an ideal, diatomic gas for the following flow processes: isentropic expansion; normal shocks; boundary layers; and shock wave boundary layer interactions. The only differences in predicted pressure ratio between nitrogen and an ideal gas that may limit the minimum operating temperatures of transonic cryogenic wind tunnels seem to occur at total pressures approaching 9atmospheres and total temperatures 10 K below the corresponding saturation temperature, where the differences approach 1 percent for both isentropic expansions and normal shocks. Several alternative cryogenic test gases - air, helium, and hydrogen - are also analyzed. Differences in air from an ideal, diatomic gas are similar in magnitude to those of nitrogen. Differences for helium and hydrogen are over an order of magnitude greater than those for nitrogen or air. Helium and hydrogen do not approximate the compressible flow of an ideal, diatomic gas.

  12. Cryogenic supplies for the TFTR neutral beam line cryopanels

    International Nuclear Information System (INIS)

    Pinter, G.

    1977-01-01

    Cryocondensing panels will be used for the Neutral Beam Lines of the TFTR to satisfy a pumping speed requirement of 2.5 x 10 6 l/s. The cryocondensing panels are fed by liquid helium (LHe), boiling at selectable temperatures of 4.5 0 K or 3.8 0 K. Liquid nitrogen (LN 2 ) panels and chevrons thermally shield the LHe panel. The closed-loop LHe supply system and the open loop LN 2 system are discussed. The helium refrigerator of minimum 1070-W capacity, together with its distribution system, and the nitrogen distribution system in the ton/hour LN 2 range is presented. Problems and their solutions in connection with the LHe system, including the distribution over a distance of 500 feet of large quantities of liquid/gas mixtures with load variations over the range of about 3 : 1, and the economies of various types of distribution lines (passive, pumped, shielded, combined), are described. The system design passed the preliminary phase. Design features and auxiliary equipment to assure dispersion of large quantities of nitrogen into the atmosphere and to permit operation under degraded cryogenic helium refrigerator performance are also discussed in Design Considerations

  13. Crygenic performance of a superfluid helium relief valve for the LHC superconducting magnets

    International Nuclear Information System (INIS)

    Danielsson, H.; Ferlin, G.; Luguet, C.

    1996-01-01

    The high-field superconducting magnets of the Large Hadron Collider (LHC) project at CERN will operate below 1.9 K in static baths of pressurized helium II. In case of resistive transition (open-quotes quenchclose quotes), the resulting pressure rise in the cryostats must be limited to below their 2 MPa design pressure. This is achieved by discharging helium at high flow-rates into a cold recovery header, normally maintained at 20 K. For this purpose, the authors have designed, built and tested a cryogenic quench relief valve with a nominal diameter of 50 mm and an opening time of below 0.1 s. The valve, which can be opened on an external trigger, also acts as a relief device actuated by the upstream pressure when it exceeds 0.4 MPa. In normal operation, the closed poppet must be helium-tight, for hydraulic and thermal separation of the magnet baths from the recovery header. Following mechanical qualification tests under vacuum, the authors have mounted the relief valve in a dedicated cryogenic measuring bench, in order to perform precision thermal measurements with pressurized helium II

  14. Cryogenic systems for proof of the principle experiment of coherent electron cooling at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yuenian; Belomestnykh, Sergey; Brutus, Jean Clifford; Lederle, Dewey; Orfin, Paul; Skaritka, John; Soria, Victor; Tallerico, Thomas; Than, Roberto [Collider Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2014-01-29

    The Coherent electron Cooling (CeC) Proof of Principle (PoP) experiment is proposed to be installed in the Relativistic Heavy Ion Collider (RHIC) to demonstrate proton and ion beam cooling with this new technique that may increase the beam luminosity in certain cases, by as much as tenfold. Within the scope of this project, a 112 MHz, 2MeV Superconducting Radio Frequency (SRF) electron gun and a 704 MHz 20MeV 5-cell SRF cavity will be installed at IP2 in the RHIC ring. The superconducting RF electron gun will be cooled in a liquid helium bath at 4.4 K. The 704 MHz 5-cell SRF cavity will be cooled in a super-fluid helium bath at 2.0 K. This paper discusses the cryogenic systems designed for both cavities. For the 112 MHz cavity cryogenic system, a condenser/boiler heat exchanger is used to isolate the cavity helium bath from pressure pulses and microphonics noise sources. For the 704 MHz 5-cell SRF cavity, a heat exchanger is also used to isolate the SRF cavity helium bath from noise sources in the sub-atmospheric pumping system operating at room temperature. Detailed designs, thermal analyses and discussions for both systems will be presented in this paper.

  15. Cryopumping of deuterium hydrogen and helium mixtures on smooth 4.2 K surfaces

    International Nuclear Information System (INIS)

    Chou, T.S.; Halama, H.J.

    1977-01-01

    The large quantities of deuterium and hydrogen to be pumped in a fusion reactor and its subsystems favor cryopumping over other pumping methods. Cryogen consumption and the operating pressure will not only depend on the gas to be pumped, but also on the amount of helium gas present in the system. In fact, residual helium pressure between pulses will determine the power dissipation of the pump, and hence, influence the choice of cryocondensation or cryosorption. In this paper we will present the results of our studies on (1) cryotrapping of helium in thick D 2 and H 2 films and hydrogen in D 2 films at 4.2 K; (2) diffusion of He and H 2 from D 2 films; (3) steady-state liquid helium consumption; (4) liquid helium consumption as a function of D 2 and H 2 fluxes being pumped; (5) liquid helium consumption as a function of He partial pressure in the system. Finally, these measurements will suggest maximum permissible He to D 2 and He to H 2 ratios in a cryocondensation pump

  16. High-efficiency pump for space helium transfer. Final Technical Report

    International Nuclear Information System (INIS)

    Hasenbein, R.; Izenson, M.G.; Swift, W.L.; Sixsmith, H.

    1991-12-01

    A centrifugal pump was developed for the efficient and reliable transfer of liquid helium in space. The pump can be used to refill cryostats on orbiting satellites which use liquid helium for refrigeration at extremely low temperatures. The pump meets the head and flow requirements of on-orbit helium transfer: a flow rate of 800 L/hr at a head of 128 J/kg. The overall pump efficiency at the design point is 0.45. The design head and flow requirements are met with zero net positive suction head, which is the condition in an orbiting helium supply Dewar. The mass transfer efficiency calculated for a space transfer operation is 0.99. Steel ball bearings are used with gas fiber-reinforced teflon retainers to provide solid lubrication. These bearings have demonstrated the longest life in liquid helium endurance tests under simulated pumping conditions. Technology developed in the project also has application for liquid helium circulation in terrestrial facilities and for transfer of cryogenic rocket propellants in space

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

    Energy Technology Data Exchange (ETDEWEB)

    Heidt, C.; Grohmann, S. [Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany and Karlsruhe Institute of Technology, Institute for Technical Thermodynamics and Refrigeration, Engler-Bunte (Germany); Süßer, M. [Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    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.

  18. Second sound scattering in superfluid helium

    International Nuclear Information System (INIS)

    Rosgen, T.

    1985-01-01

    Focusing cavities are used to study the scattering of second sound in liquid helium II. The special geometries reduce wall interference effects and allow measurements in very small test volumes. In a first experiment, a double elliptical cavity is used to focus a second sound wave onto a small wire target. A thin film bolometer measures the side scattered wave component. The agreement with a theoretical estimate is reasonable, although some problems arise from the small measurement volume and associated alignment requirements. A second cavity is based on confocal parabolas, thus enabling the use of large planar sensors. A cylindrical heater produces again a focused second sound wave. Three sensors monitor the transmitted wave component as well as the side scatter in two different directions. The side looking sensors have very high sensitivities due to their large size and resistance. Specially developed cryogenic amplifers are used to match them to the signal cables. In one case, a second auxiliary heater is used to set up a strong counterflow in the focal region. The second sound wave then scatters from the induced fluid disturbances

  19. Cryogenic Propellant Storage and Transfer

    Data.gov (United States)

    National Aeronautics and Space Administration — Space Flight Demonstration development has been canceled in favor of a ground test bed development for of passive/active cryogenic propellant storage, transfer, and...

  20. Cryogenics of the new superconducting accelerator Nuclotron. The first year under operation

    International Nuclear Information System (INIS)

    Baldin, A.M.; Agapov, N.N.; Belushkin, V.A.; D'yachkov, E.I.; Khodzhibagiyan, G.G.; Kovalenko, A.D.; Kuznetsov, G.L.; Matyushevskij, E.A.; Smirnov, A.A.; Sukhanova, A.K.

    1995-01-01

    The 6 GeV superconducting synchrotron was commissioned in March 1993 at the Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna. Four runs of the total duration about 1000 hours were provided from March 1993 to March 1994. The cooling of the accelerator magnetic system of 250 meters long was performed by two helium refrigerators with a capacity of 1.6 kw at 4.5 K each. The magnets were refrigerated by a two-phase helium flow. All 160 magnets are connected in parallel to the supply and return helium headers. The description and operational characteristics of the Nuclotron cryogenic system are presented. 7 refs., 5 figs., 1 tab

  1. Cryogenic, Absolute, High Pressure Sensor

    Science.gov (United States)

    Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

    2001-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  2. Cryogenic High Pressure Sensor Module

    Science.gov (United States)

    Chapman, John J. (Inventor); Shams, Qamar A. (Inventor); Powers, William T. (Inventor)

    1999-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  3. Cryogenic foam insulation: Abstracted publications

    Science.gov (United States)

    Williamson, F. R.

    1977-01-01

    A group of documents were chosen and abstracted which contain information on the properties of foam materials and on the use of foams as thermal insulation at cryogenic temperatures. The properties include thermal properties, mechanical properties, and compatibility properties with oxygen and other cryogenic fluids. Uses of foams include applications as thermal insulation for spacecraft propellant tanks, and for liquefied natural gas storage tanks and pipelines.

  4. A Piezoelectric Cryogenic Heat Switch

    Science.gov (United States)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  5. Exotic helium molecules

    International Nuclear Information System (INIS)

    Portier, M.

    2007-12-01

    We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range 4 He 2 (2 3 S 1 -2 3 P 0 ) molecule, or a 4 He 2 (2 3 S 1 -2 3 S 1 ) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 ± 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range 4 He 2 (2 3 S 1 -2 3 S 1 ) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime τ = (1.4 ± 0.3) μs is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

  6. Electronic properties of physisorbed helium

    International Nuclear Information System (INIS)

    Kossler, Sarah

    2011-01-01

    This thesis deals with electronic excitations of helium physisorbed on metal substrates. It is studied to what extent the electronic properties change compared to the gas phase due to the increased helium density and the proximity of the metal. Furthermore, the influence of different substrate materials is investigated systematically. To this end, up to two helium layers were adsorbed onto Ru (001), Pt (111), Cu (111), and Ag (111) surfaces in a custom-made cryostat. These samples were studied spectroscopically using synchrotron radiation and a time-of-flight detector. The experimental results were then analyzed in comparison with extensive theoretical model calculations.

  7. Electronic properties of physisorbed helium

    Energy Technology Data Exchange (ETDEWEB)

    Kossler, Sarah

    2011-09-22

    This thesis deals with electronic excitations of helium physisorbed on metal substrates. It is studied to what extent the electronic properties change compared to the gas phase due to the increased helium density and the proximity of the metal. Furthermore, the influence of different substrate materials is investigated systematically. To this end, up to two helium layers were adsorbed onto Ru (001), Pt (111), Cu (111), and Ag (111) surfaces in a custom-made cryostat. These samples were studied spectroscopically using synchrotron radiation and a time-of-flight detector. The experimental results were then analyzed in comparison with extensive theoretical model calculations.

  8. Cryogenic Electric Motor Tested

    Science.gov (United States)

    Brown, Gerald V.

    2004-01-01

    Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.

  9. Cryogenic Permanent Magnet Undulators

    International Nuclear Information System (INIS)

    Chavanne, J.; Lebec, G.; Penel, C.; Revol, F.; Kitegi, C.

    2010-01-01

    For an in-vacuum undulator operated at small gaps the permanent magnet material needs to be highly resistant to possible electron beam exposure. At room temperature, one generally uses Sm 2 Co 17 or high coercivity NdFeB magnets at the expense of a limited field performance. In a cryogenic permanent magnet undulator (CPMU), at a temperature of around 150 K, any NdFeB grade reveals a coercivity large enough to be radiation resistant. In particular, very high remanence NdFeB material can be used to build undulators with enhanced field and X-ray brilliance at high photon energy provided that the pre-baking of the undulator above 100 deg. C can be eliminated. The ESRF has developed a full scale 2 m long CPMU with a period of 18 mm. This prototype has been in operation on the ID6 test beamline since January 2008. A significant effort was put into the characterization of NdFeB material at low temperature, the development of dedicated magnetic measurement systems and cooling methods. The measured heat budget with beam is found to be larger than expected without compromising the smooth operation of the device. Leading on from this first experience, new CPMUs are currently being considered for the upgrade of the ESRF.

  10. Design and development of a device management platform for EAST cryogenic system

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Zhiwei, E-mail: zzw@ipp.ac.cn; Lu, Xiaofei, E-mail: xiaofeilu@ipp.ac.cn; Zhuang, Ming, E-mail: zhm@ipp.ac.cn; Hu, Liangbing, E-mail: huliangbing@ipp.ac.cn; Xia, Genhai, E-mail: xgh@ipp.ac.cn

    2014-05-15

    Highlights: • A device management platform for EAST cryogenic system based on DCS is designed. • This platform enhances the integrity and continuity of system device information. • It can help predictive maintenance and device management decision. - Abstract: EAST cryogenic system is one of the critical sub-systems of the EAST tokamak device. It is a large scale helium cryoplant, which adopts distributed control system to realize monitoring and control of the cryogenic process and devices. However, the maintenance and management of most field devices are still in the corrective maintenance or traditional preventive maintenance stage. Under maintained or over maintained problems widely exist, which could cause devices fault and increase operation costs. Therefore, a device management platform is proposed for a safe and steady operation as well as fault diagnosis and predictive maintenance of EAST cryogenic system. This paper presents the function design and architecture design of the cryogenic device management platform. This platform is developed based on DeltaV DCS and acquires monitoring data through OPC protocol. It consists of three pillars, namely device information management, device condition management, and device performance monitoring. The development and implementation of every pillar are illustrated in detail in this paper. Test results and discussions are presented in the end.

  11. Operation of Cryogenic Facility in e-way at Tata Institute of Fundamental Research, Mumbai, India

    International Nuclear Information System (INIS)

    Srinivasan, K V

    2012-01-01

    In an attempt towards the development of modern, model and paperless cryogenic facility, the Low Temperature Facility of Tata Institute of Fundamental Research, at Mumbai, India; carried out many automation works using programmable logic controller (PLC) and other modern electronic tools, with the objective of bringing the entire plant operation to your palm whenever and wherever you are. Efficiency in the plant operation by keeping a watch on the plant healthiness, advance indication about the possible plant problem by means of pre-warning alarms, so that the remedial action can be taken well prior to the actual failure affects the plant operation, reduction in plant down time were achieved by the automation works. Large size in our cryogen production, controlling the complicated helium liquefier, meeting the uninterrupted supply of cryogen to the users on “any time availability basis,” safety in handling cryogens and high pressure gas, effective usage of limited skilled manpower etc., all these requirements call for the definite need of modern electronic gears and gadgets. This paper will describe in details about the automation works carried out at our cryogenic facility at TIFR.

  12. Cryogenic trapping of keV ion beams at the CSR prototype

    Energy Technology Data Exchange (ETDEWEB)

    Menk, Sebastian; Blaum, Klaus; Froese, Michael; Grieser, Manfred; Lange, Michael; Orlov, Dimitry; Sieber, Thomas; Hahn, Robert von; Varju, Jozef; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Heber, Oded; Rappaport, Michael; Zajfman, Daniel [Weizmann Institut of Science, Rehovot (Israel)

    2009-07-01

    A Cryogenic Trap for Fast ion beams (CTF) was built to explore cooling techniques and test thermal decoupling of ion optics for the development of the electrostatic Cryogenic Storage Ring (CSR). These challenging projects will lead to a new experimental field of atomic and molecular physics with keV ion beams. The cold conditions of 2-10 K minimize the blackbody radiation field and are expected to lead to extremely low restgas densities (equivalent pressure at room temperature {approx}10{sup -13} mbar) which result in long storage lifetimes and for molecular ions to radiative cooling to their ro-vibrational ground states. The CTF consists of two stacks of electrostatic mirror electrodes allowing the storage of up to 20 keV ion beams. Cryogenic ion beam storage has been realized with this device using a liquid helium refrigeration system to cool down the experimental trapping area to few-Kelvin cryogenic temperatures and experiments with cryogenically trapped molecular nitrogen ions have been performed to verify the low vacuum conditions by measuring their storage lifetimes.

  13. Periodic flow hydrodynamic resistance parameters for woven screen matrices at cryogenic temperatures

    Science.gov (United States)

    Perrella, M. D.; Ghiaasiaan, S. M.

    2017-12-01

    The regenerator is a critical component in all Stirling and Pulse Tube cryocoolers. It generally consists of a microporous metallic or rare-earth filler material contained within a cylindrical shell. Accurate modelling of the hydrodynamic and thermal behaviour of different regenerator materials is crucial to the successful design of cryogenic systems. Previous investigations have used experimental measurements at steady and periodic flow conditions in conjunction with pore-level CFD analysis to determine the pertinent hydrodynamic parameters, namely the Darcy permeability and Forchheimer coefficients. Due to the difficulty associated with experimental measurement at cryogenic temperatures, past investigations were mostly performed at ambient conditions and their results are assumed to be appropriate for cryogenic temperatures. In this study, a regenerator filled with woven screen matrices such as 400 mesh T316 stainless steel were assembled and experimentally tested under periodic helium flow at cryogenic temperatures. The mass flow and pressure drop data were analysed using CFD to determine the dimensionless friction factor, Darcy Permeability and Forchheimer coefficients. These results are compared to previous investigations at ambient temperature conditions, and the relevance of room-temperature models and correlations to cryogenic temperatures is critically assessed.

  14. Simulation and experimental research of heat leakage of cryogenic transfer lines

    Science.gov (United States)

    Deng, B. C.; Xie, X. J.; Pan, W.; Jiang, R. X.; Li, J.; Yang, S. Q.; Li, Q.

    2017-12-01

    The heat leakage of cryogenic transfer lines directly influences the performance of large-scale helium refrigerator. In this paper, a thermal model of cryogenic transfer line considering numerical simulation of support coupled with MLI was established. To validate the model, test platform of cryogenic transfer lines with the merits of disassembly outer pipe and changeable easily multi-layer insulation has been built. The experimental results of heat leakage through overall length of cryogenic transfer lines, support and multi-layer insulation were obtained. The heat leakages of multi-layer insulation, a support and the overall leakage are 1.02 W/m, 0.44 W and 1.46 W/m from experimental data, respectively. The difference of heat leakage of MLI between experiment and simulation were less than 5%. The temperature distribution of support and MLI obtained in presented model in good agreement with experimental data. It is expected to reduce the overall heat leakage of cryogenic transfer lines further by optimizing structure of support based on the above thermal model and test platform in this paper.

  15. Helium cooling of fusion reactors

    International Nuclear Information System (INIS)

    Wong, C.P.C.; Baxi, C.; Bourque, R.; Dahms, C.; Inamati, S.; Ryder, R.; Sager, G.; Schleicher, R.

    1994-01-01

    On the basis of worldwide design experience and in coordination with the evolution of the International Thermonuclear Experimental Reactor (ITER) program, the application of helium as a coolant for fusion appears to be at the verge of a transition from conceptual design to engineering development. This paper presents a review of the use of helium as the coolant for fusion reactor blanket and divertor designs. The concept of a high-pressure helium cooling radial plate design was studied for both ITER and PULSAR. These designs can resolve many engineering issues, and can help with reaching the goals of low activation and high performance designs. The combination of helium cooling, advanced low-activation materials, and gas turbine technology may permit high thermal efficiency and reduced costs, resulting in the environmental advantages and competitive economics required to make fusion a 21st century power source. ((orig.))

  16. Laser spectroscopy of antiprotonic helium

    CERN Document Server

    Hori, M

    2005-01-01

    When antiprotons (i.e. the antimatter counterpart of protons) are stopped in helium gas, 97% of them annihilate within picoseconds by reacting with the helium nuclei; a 3% fraction, however, survive with an anomalously long lifetime of several microseconds. This longevity is due to the formation of antiprotonic helium, which is a three-body Rydberg atom composed of an antiproton, electron, and helium nucleus. The ASACUSA experimental collaboration has recently synthesized large numbers of these atoms using CERN's Antiproton Decelerator facility, and measured the atom's transition frequencies to 60 parts per billion by laser spectroscopy. By comparing the experimental results with recent three-body QED calculations and the known antiproton cyclotron frequency, we were able to show that the antiproton mass and charge are the same as the corresponding proton values to a precision of 10 parts per billion. Ongoing and future series of experiments will further improve the experimental precision by using chirp-compe...

  17. High Accuracy Vector Helium Magnetometer

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed HAVHM instrument is a laser-pumped helium magnetometer with both triaxial vector and omnidirectional scalar measurement capabilities in a single...

  18. Dynamics of Superfluid Helium in Low-Gravity

    Science.gov (United States)

    Frank, David J.

    1997-01-01

    This report summarizes the work performed under a contract entitled 'Dynamics of Superfluid Helium in Low Gravity'. This project performed verification tests, over a wide range of accelerations of two Computational Fluid Dynamics (CFD) codes of which one incorporates the two-fluid model of superfluid helium (SFHe). Helium was first liquefied in 1908 and not until the 1930s were the properties of helium below 2.2 K observed sufficiently to realize that it did not obey the ordinary physical laws of physics as applied to ordinary liquids. The term superfluidity became associated with these unique observations. The low temperature of SFHe and it's temperature unifonrmity have made it a significant cryogenic coolant for use in space applications in astronomical observations with infrared sensors and in low temperature physics. Superfluid helium has been used in instruments such as the Shuttle Infrared Astronomy Telescope (IRT), the Infrared Astronomy Satellite (IRAS), the Cosmic Background Observatory (COBE), and the Infrared Satellite Observatory (ISO). It is also used in the Space Infrared Telescope (SIRTF), Relativity Mission Satellite formally called Gravity Probe-B (GP-B), and the Test of the Equivalence Principle (STEP) presently under development. For GP-B and STEP, the use of SFHE is used to cool Superconducting Quantum Interference Detectors (SQUIDS) among other parts of the instruments. The Superfluid Helium On-Orbit Transfer (SHOOT) experiment flown in the Shuttle studied the behavior of SFHE. This experiment attempted to get low-gravity slosh data, however, the main emphasis was to study the low-gravity transfer of SFHE from tank to tank. These instruments carried tanks of SFHE of a few hundred liters to 2500 liters. The capability of modeling the behavior of SFHE is important to spacecraft control engineers who must design systems that can overcome disturbances created by the movement of the fluid. In addition instruments such as GP-B and STEP are very

  19. Cryogenics bringing the temperature down, underground

    CERN Multimedia

    2005-01-01

    The first 600m of the LHC cryogenic distribution line (QRL), which will feed the accelerator's superconducting magnets, has passed initial validating tests of its mechanical design at room and cryogenic temperatures.

  20. Cryogenic safety organisation at CERN

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    With Safety being a top priority of CERN’s general policy, the Organisation defines and implements a Policy that sets out the general principles governing Safety at CERN. To the end of the attainment of said Safety objectives, the organic units (owners/users of the equipment) are assigned the responsibility for the implementation of the CERN Safety Policy at all levels of the organization, whereas the Health and Safety and Environmental Protection Unit (HSE) has the role of providing assistance for the implementation of the Safety Policy, and a monitoring role related to the implementation of continuous improvement of Safety, compliance with the Safety Rules and the handling of emergency situations. This talk will elaborate on the roles, responsibilities and organisational structure of the different stakeholders within the Organization with regards to Safety, and in particular to cryogenic safety. The roles of actors of particular importance such as the Cryogenic Safety Officers (CSOs) and the Cryogenic Sa...

  1. Cryogenic testing of fluoropolymer-coated stainless steel tubing

    International Nuclear Information System (INIS)

    Dooley, J.B.

    1989-11-01

    Stainless steel tubing coated internally with two different types of fluorinated polymers were subjected to microscopic examination after a welding operation had been performed on the tubing. The welded assemblies were photographed and subjected to repeated cycles between liquid helium and room temperature. The green tetrafluoroethylene (TFE) coating peeled back in the area subjected to welding heat and displayed cracking all over its surface without regard to proximity to the weld area. The dark fluorinated ethylene propylene (FEP) coating showed a tendency to char or burn away progressively in the weld area. The dark (FEP) coating did not crack as extensively as the green TFE coating, but did show a few areas of ''crazing'' or cracking of the topmost surface after cryogenic exposure. 12 figs

  2. Studies on cryogenic distillation columns for hydrogen isotope separation

    International Nuclear Information System (INIS)

    Kinoshita, Masahiro

    1984-08-01

    Cryogenic distillation is applicable to a number of situations. The feed condition, column cascade configuration, input and output specifications vary greatly from situation to situation. In the mainstream fuel circulation system for a fusion reactor, the feed composition may fluctuate greatly during the operation. The radiological standards for tritium lost to the environment are increasingly becoming stricter. Systematic studies are needed to achieve the goal of long-term operation meeting the strict requirements for products even under great fluctuation of the feed condition in all the situations. The present report gives a critical, brief review of the studies which have been made by the author. The subjects treated are development of computer simulation procedures, analysis on an H-T separation column with a feedback stream, dynamics and control, proposal of a new cascade, analysis on helium effects on column behavior, start-up analysis for a cascade, and preliminary experimental study on dependence of HETP on operational conditions. (author)

  3. Fabrication and characterization of cryogenic targets for inertial confinement fusion

    International Nuclear Information System (INIS)

    Rieger, H.; Kim, K.

    1979-08-01

    A new technique has been developed which is capable of fabricating uniform cryogenic targets for use in inertial confinement fusion. The essence of the technique is to directly wet a target with a cold helium gas jet, which results in freezing of the DT mixture contained in the target. A controlled amount of current is pulsed through a heater wire surrounding the target, giving rise to fast evaporation and refreezing of the DT-condensate into a uniform layer. Experiments, which have been performed with D 2 -filled glass microshells, successfully produce uniform layers of both liquid and solid D 2 inside the glass shells. A set of data illustrating the technique is presented and analyzed

  4. Control and operation cost optimization of the HISS cryogenic system

    International Nuclear Information System (INIS)

    Porter, J.; Bieser, F.; Anderson, D.

    1983-08-01

    The Heavy Ion Spectrometer System (HISS) relies upon superconducting coils of cryostable design to provide a maximum particle bending field of 3 tesla. A previous paper describes the cryogenic facility including helium refrigeration and gas management. This paper discusses a control strategy which has allowed full time unattended operation, along with significant nitrogen and power cost reductions. Reduction of liquid nitrogen consumption has been accomplished by making use of the sensible heat available in the cold exhaust gas. Measured nitrogen throughput agrees with calculations for sensible heat utilization of zero to 70%. Calculated consumption saving over this range is 40 liters per hour for conductive losses to the supports only. The measured throughput differential for the total system is higher

  5. Visualization in cryogenic environment: Application to two-phase studies

    Science.gov (United States)

    Rousset, Bernard; Chatain, Denis; Puech, Laurent; Thibault, Pierre; Viargues, François; Wolf, Pierre-Etienne

    2009-10-01

    This paper reviews recent technical developments devoted to the study of cryogenic two-phase fluids. These techniques span from simple flow visualization to quantitative measurements of light scattering. It is shown that simple flow pattern configurations are obtained using classical optical tools (CCD cameras, endoscopes), even in most severe environments (high vacuum, high magnetic field). Quantitative measurements include laser velocimetry, particle sizing, and light scattering analysis. In the case of magnetically compensated gravity boiling oxygen, optical access is used to control the poistioning of a bubble subject to buoyancy forces in an experimental cell. Flow visualization on a two-phase superfluid helium pipe-flow, performed as a support of LHC cooldown studies, leads to flow pattern characterization. Visualization includes stratified and atomized flows. Thanks to the low refractive index contrast between the liquid and its vapor, quantitative results on droplet densities can be obtained even in a multiple scattering regime.

  6. Cryogenic Semiconductor Detectors: Simulation of Signal Formation & Irradiation Beam Test

    CERN Document Server

    AUTHOR|(CDS)2091318; Stamoulis, G; Vavougios, D

    The Beam Loss Monitoring system of the Large Hadron Collider is responsible for the pro- tection of the machine from damage and for the prevention of a magnet quench. Near the interaction points of the LHC, in the triplet magnets area, the BLMs are sensitive to the collision debris, limiting their ability to distinguish beam loss signal from signal caused due to the collision products. Placing silicon & diamond detectors inside the cold mass of the mag- nets, in liquid helium temperatures, would provide significant improvement to the precision of the measurement of the energy deposition in the superconducting coil of the magnet. To further study the signal formation and the shape of the transient current pulses of the aforementioned detectors in cryogenic temperatures, a simulation application has been developed. The application provides a fast way of determining the electric field components inside the detectors bulk and then introduces an initial charge distribution based on the properties of the radiat...

  7. Cryogenic instrumentation for ITER magnets

    Science.gov (United States)

    Poncet, J.-M.; Manzagol, J.; Attard, A.; André, J.; Bizel-Bizellot, L.; Bonnay, P.; Ercolani, E.; Luchier, N.; Girard, A.; Clayton, N.; Devred, A.; Huygen, S.; Journeaux, J.-Y.

    2017-02-01

    Accurate measurements of the helium flowrate and of the temperature of the ITER magnets is of fundamental importance to make sure that the magnets operate under well controlled and reliable conditions, and to allow suitable helium flow distribution in the magnets through the helium piping. Therefore, the temperature and flow rate measurements shall be reliable and accurate. In this paper, we present the thermometric chains as well as the venturi flow meters installed in the ITER magnets and their helium piping. The presented thermometric block design is based on the design developed by CERN for the LHC, which has been further optimized via thermal simulations carried out by CEA. The electronic part of the thermometric chain was entirely developed by the CEA and will be presented in detail: it is based on a lock-in measurement and small signal amplification, and also provides a web interface and software to an industrial PLC. This measuring device provides a reliable, accurate, electromagnetically immune, and fast (up to 100 Hz bandwidth) system for resistive temperature sensors between a few ohms to 100 kΩ. The flowmeters (venturi type) which make up part of the helium mass flow measurement chain have been completely designed, and manufacturing is on-going. The behaviour of the helium gas has been studied in detailed thanks to ANSYS CFX software in order to obtain the same differential pressure for all types of flowmeters. Measurement uncertainties have been estimated and the influence of input parameters has been studied. Mechanical calculations have been performed to guarantee the mechanical strength of the venturis required for pressure equipment operating in nuclear environment. In order to complete the helium mass flow measurement chain, different technologies of absolute and differential pressure sensors have been tested in an applied magnetic field to identify equipment compatible with the ITER environment.

  8. Structure design and simulation research of active magnetic bearing for helium centrifugal cold compressor

    Science.gov (United States)

    Y Zhang, S.; Pan, W.; Wei, C. B.; Wu, J. H.

    2017-12-01

    Helium centrifugal cold compressors are utilized to pump gaseous helium from saturated liquid helium tank to obtain super-fluid helium in cryogenic refrigeration system, which is now being developed at TIPC, CAS. Active magnetic bearing (AMB) is replacing traditional oil-fed bearing as the optimal supporting assembly for cold compressor because of its many advantages: free of contact, high rotation speed, no lubrication and so on. In this paper, five degrees of freedom for AMB are developed for the helium centrifugal cold compressor application. The structure parameters of the axial and radial magnetic bearings as well as hardware and software of the electronic control system is discussed in detail. Based on modal analysis and critical speeds calculation, a control strategy combining PID arithmetic with other phase compensators is proposed. Simulation results demonstrate that the control method not only stables AMB system but also guarantees good performance of closed-loop behaviour. The prior research work offers important base and experience for test and application of AMB experimental platform for system centrifugal cold compressor.

  9. Recent run-time experience and investigation of impurities in turbines circuit of Helium plant of SST-1

    International Nuclear Information System (INIS)

    Panchal, P.; Panchal, R.; Patel, R.

    2013-01-01

    One of the key sub-systems of Steady State superconducting Tokamak (SST-1) is cryogenic 1.3 kW at 4.5 K Helium refrigerator/liquefier system. The helium plant consists of 3 nos. of screw compressors, oil removal system, purifier and cold-box with 3 turbo expanders (turbines) and helium cold circulator. During the recent SST-1 plasma campaigns, we observed high pressure drop of the order of 3 bar between the wheel outlet of turbine A and the wheel inlet of turbine - B. This was significant higher values of pressures drop across turbines, which reduced the speed of turbine A and B and in turn reduced the overall plant capacity. The helium circuits in the plant have 10-micron filter at the mouth of turbine - B. Initially, major suspects of such high blockage are assumed to be air-impurity, dust particles or collapse of filter. Several breaks in plant operation have been taken to warm up the turbines circuits up to 90 K to remove condensation of air-impurities at filter. Still this exercise did not solve blockage of filter in turbine circuits. A detailed investigation exercise with air/water regeneration and rinsing of cold box as well as purification of helium gas in buffer tanks are carried out to remove air impurities from cold-box. A trial run of cold box was executed in liquefier mode with turbines up to cryogenic temperatures and solved blockage in turbine circuits. The paper describes run-time experience of helium plant with helium impurity in turbine circuits, methods to remove impurity, demonstration of turbine performance and lessons learnt during this operation. (author)

  10. Reduction of hydrocarbon impurities in 200 L/H helium liquefier-refrigerator system

    International Nuclear Information System (INIS)

    Yamada, Shuichi; Mito, Toshiyuki; Nishimura, Arata

    1993-11-01

    A cryogenic system with the capacity of 200 1/h or 500 W at 4.4 K has been operated to develop the superconducting conductors and coils for the LHD. The system has contributed in various superconducting technologies along with the dc 75kA power supply and 10 MN mechanical testing machine, and completed the basic R and D works of the LHD. On the way of operating the cryogenic system, impurity densities of hydrocarbon gases in circulating helium gas became much larger than the expected values for this cryogenic system, so that the densities of some impurity gases were carefully monitored in reference to the operational conditions of circulating compressor by using a gas chromatography. Impurity gas densities of oxygen, nitrogen and ethane increased obviously, when the output capacity of the compressor was reduced. In a two-stage oil injected compression system with a variable stroke mechanism for a first stage, a reduction in the capacity of the first stage leads to a larger compression ratio for the second stage, and the temperature of the injected oil becomes higher. The production of the impurities in the helium might be caused by cracking a part of injected oil in the compressor. The compressor, therefore, was reconstructed such that the injection oil is supplied sufficiently and the compression ratio division becomes even for each stage. It was confirmed that the impurities are not produced now after modification. (author)

  11. Reduction of hydrocarbon impurities in 200 l/h helium liquefier-refrigerator system

    Science.gov (United States)

    Yamada, Shuichi; Mito, Toshiyuki; Nishimura, Arata; Takahata, Kazuya; Satoh, Sadao; Yamamoto, Junya; Yamamura, Hidemasa; Masuda, Kaoru; Kashihara, Shinichirou; Fukusada, Katsuaki

    1993-11-01

    A cryogenic system with the capacity of 200 l/h or 500 W at 4.4 K was developed in order to supply the superconducting conductors and coils of the LHD. As a by-product of operating the cryogenic system, the impurity densities of hydrocarbon gases in the circulating helium gas became much larger than the expected values for this cryogenic system. So much larger in fact, that it became necessary to carefully monitor the operational conditions of the circulating compressor by means of gas chromatography. Impurity gas densities of oxygen, nitrogen, and ethane increased significantly when the output capacity of the compressor was reduced. In a two-stage oil injected compression system, with a variable stroke mechanism for a first stage, a reduction in the capacity of the first stage leads to a larger compression ratio for the second stage, and the temperature of the injected oil becomes higher. The production of the impurities in the helium might be caused by decomposition of the injected oil in the compressor. The compressor, therefore, was reconstructed such that the injection oil is supplied sufficiently, and the compression ratio division becomes even for each stage. It was confirmed that the impurities were not produced after the modification.

  12. A cryogenic tensile testing apparatus for micro-samples cooled by miniature pulse tube cryocooler

    International Nuclear Information System (INIS)

    Chen, L B; Liu, S X; Gu, K X; Zhou, Y; Wang, J J

    2015-01-01

    This paper introduces a cryogenic tensile testing apparatus for micro-samples cooled by a miniature pulse tube cryocooler. At present, tensile tests are widely applied to measure the mechanical properties of materials; most of the cryogenic tensile testing apparatus are designed for samples with standard sizes, while for non-standard size samples, especially for microsamples, the tensile testing cannot be conducted. The general approach to cool down the specimens for tensile testing is by using of liquid nitrogen or liquid helium, which is not convenient: it is difficult to keep the temperature of the specimens at an arbitrary set point precisely, besides, in some occasions, liquid nitrogen, especially liquid helium, is not easily available. To overcome these limitations, a cryogenic tensile testing apparatus cooled by a high frequency pulse tube cryocooler has been designed, built and tested. The operating temperatures of the developed tensile testing apparatus cover from 20 K to room temperature with a controlling precision of ±10 mK. The apparatus configurations, the methods of operation and some cooling performance will be described in this paper. (paper)

  13. Development of a cryogenic radiation detector for mapping radio frequency superconducting cavity field emissions

    Energy Technology Data Exchange (ETDEWEB)

    Danny Dotson; John Mammosser

    2005-05-01

    Field emissions in a super conducting helium cooled RF cavity and the production of radiation (mostly X-Rays) have been measured externally on cryomodules at Jefferson Lab since 1991. External measurements are limited to radiation energies above 100 keV due to shielding of the stainless steel cryogenic body. To measure the onset of and to map field emissions from a superconducting cavity requires the detecting instrument be inside the shield and within the liquid Helium. Two possible measurement systems are undergoing testing at JLab. A CsI detector array set on photodiodes and an X-Ray film camera with a fixed aperture. Several devices were tested in the cell with liquid Helium without success. The lone survivor, a CsI array, worked but saturated at high power levels due to backscatter. The array was encased in a lead shield with a slit opening set to measure the radiation emitted directly from the cell eliminating a large portion of the backscatter. This is a work in progress and te sting should be complete before the PAC 05. The second system being tested is passive. It is a shielded box with an aperture to expose radiation diagnostic film located inside to direct radiation from the cell. Developing a technique for mapping field emissions in cryogenic cells will assist scientists and engineers in pinpointing any surface imperfections for examination.

  14. A dynamic model for helium core heat exchangers

    International Nuclear Information System (INIS)

    Schiesser, W.E.; Shih, H.J.; Hartozog, D.G.; Herron, D.M.; Nahmias, D.; Stuber, W.G.; Hindmarsh, A.C.

    1990-04-01

    To meet the helium (He) requirements of the superconducting supercollider (SSC), the cryogenic plants must be able to respond to time-varying loads. Thus the design and simulation of the cryogenic plants requires dynamic models of their principal components, and in particular, the core heat exchangers. In this paper, we detail the derivation and computer implementation of a model for core heat exchangers consisting of three partial differential equations (PDES) for each fluid stream (the continuity, energy and momentum balances for the He), and one PDE for each parting sheet (the energy balance for the parting sheet metal); the PDEs have time and axial position along the exchanger as independent variables. The computer code can accommodate any number of fluid streams and parting sheets in an adiabatic group. Features of the code include: rigorous or approximate thermodynamic properties for He, upwind and downwind approximation of the PDE spatial derivatives, and sparse matrix time integration. The outputs from the code include the time-dependent axial profiles of the fluid He mass flux, density, pressure, temperature, internal energy and enthalpy. The code is written in transportable Fortran 77, and can therefore be executed on essentially any computer

  15. A dynamic model for helium core heat exchangers

    International Nuclear Information System (INIS)

    Schiesser, W.E.; Shih, H.J.; Hartzog, D.G.; Herron, D.M.; Nahmias, D.; Stuber, W.G.; Hindmarsh, A.C.

    1990-01-01

    To meet the helium (He) requirements of the superconducting supercollider (SSC), the cryogenic plants must be able to respond to time-varying loads. Thus the design and simulation of the cryogenic plants requires dynamic models of their principal components, and in particular, the core heat exchangers. In this paper, we detail the derivation and computer implementation of a model for core heat exchangers consisting of three partial differential equations (PDEs) for each fluid stream (the continuity, energy and momentum balances for the He), and one PDE for each parting sheet (the energy balance for the parting sheet metal); the PDEs have time and axial position along the exchanger as independent variables. The computer code can accommodate any number of fluid streams and parting sheets in an adiabatic group. Features of the code include: rigorous or approximate thermodynamic properties for He, upwind and downwind approximation of the PDE spatial derivatives, and sparse matrix time integration. The outputs from the code include the time-dependent axial profiles of the fluid He mass flux, density, pressure, temperature, internal energy and enthalpy. The code is written in transportable Fortran 77, and can therefore be executed on essentially any computer. 10 refs., 10 figs

  16. Fermilab Muon Campus g-2 Cryogenic Distribution Remote Control System

    Energy Technology Data Exchange (ETDEWEB)

    Pei, L.; Theilacker, J.; Klebaner, A.; Soyars, W.; Bossert, R.

    2015-11-05

    The Muon Campus (MC) is able to measure Muon g-2 with high precision and comparing its value to the theoretical prediction. The MC has four 300 KW screw compressors and four liquid helium refrigerators. The centerpiece of the Muon g-2 experiment at Fermilab is a large, 50-foot-diameter superconducting muon storage ring. This one-of-a-kind ring, made of steel, aluminum and superconducting wire, was built for the previous g-2 experiment at Brookhaven. Due to each subsystem has to be far away from each other and be placed in the distant location, therefore, Siemens Process Control System PCS7-400, Automation Direct DL205 & DL05 PLC, Synoptic and Fermilab ACNET HMI are the ideal choices as the MC g-2 cryogenic distribution real-time and on-Line remote control system. This paper presents a method which has been successfully used by many Fermilab distribution cryogenic real-time and On-Line remote control systems.

  17. Cryogenics around the 11.7 T MRI Iseult magnet

    International Nuclear Information System (INIS)

    Bredy, P.; Belorgey, J.; Chesny, P.; Hervieu, B.; Lannou, H.; Juster, F. P.; Abdel-Maksoud, W.; Mayri, C.; Molinie, F.; Payn, A.

    2010-01-01

    As part of the Iseult/Inumac project, the development of a 500 MHz whole body MRI magnet has been launched in 2006. This magnet with a central field of 11.7 T in a warm bore of 900 mm has outstanding specifications with respect to usual MRI systems. The normal operation of this magnet will need the construction of a cryo-plant able to cool its superconducting coils with pressurized HeII 1.8 K. A helium liquefier and 4.2 K/1.8 K refrigeration stage will be installed in the vicinity of the magnet. Before that, a magnet test facility (Seht-'station d'essais huit teslas') installed at CEA/Saclay has been built in order to validate technical and control-process aspects during all operating phases: cooling down, nominal operation, quench event. The cryogenic system has been designed according to the principles foreseen for Iseult. The facility integration, commissioning, and operating results will be presented. The design of the final cryogenic installation for Iseult magnet, adapted to the facility experiences, is previously described. (authors)

  18. Superconducting magnets and cryogenics: proceedings

    International Nuclear Information System (INIS)

    Dahl, P.F.

    1986-01-01

    Separate abstracts were prepared for 70 papers in these workshop proceeedings. Topics covered include: superconducting accelerator magnet research and development; superconductor development; electrical measurements; magnet design and construction methods; field correction methods; power schemes and quench protection; cryogenic systems; and magnet measurements

  19. Radiation hard cryogenic silicon detectors

    International Nuclear Information System (INIS)

    Casagrande, L.; Abreu, M.C.; Bell, W.H.; Berglund, P.; Boer, W. de; Borchi, E.; Borer, K.; Bruzzi, M.; Buontempo, S.; Chapuy, S.; Cindro, V.; Collins, P.; D'Ambrosio, N.; Da Via, C.; Devine, S.; Dezillie, B.; Dimcovski, Z.; Eremin, V.; Esposito, A.; Granata, V.; Grigoriev, E.; Hauler, F.; Heijne, E.; Heising, S.; Janos, S.; Jungermann, L.; Konorov, I.; Li, Z.; Lourenco, C.; Mikuz, M.; Niinikoski, T.O.; O'Shea, V.; Pagano, S.; Palmieuri, V.G.; Paul, S.; Pirollo, S.; Pretzl, K.; Rato, P.; Ruggiero, G.; Smith, K.; Sonderegger, P.; Sousa, P.; Verbitskaya, E.; Watts, S.; Zavrtanik, M.

    2002-01-01

    It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, 'resuscitate' when operated at temperatures below 130 K. This is often referred to as the 'Lazarus effect'. The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors

  20. LHC Cryogenics on the mend

    CERN Multimedia

    2004-01-01

    On 29 September, repairs began on the LHC cryogenic distribution line, or QRL, to replace a faulty part that occurs in the hundreds of elements of the line that are already on-site. The Accelerator Technology Department is designing a work programme to finish the repairs as soon as possible and minimize delays to the rest of the LHC project.

  1. Champagne for the cryogenics teams

    CERN Multimedia

    2005-01-01

    Christmas has come early for the LHC as a complete sector of the cryogenic distribution line has been operating at 10 degrees Kelvin (-263°C) for the past two weeks, just a few degrees above the machine's nominal operating temperature.

  2. Cryogenic detectors for particle physics

    International Nuclear Information System (INIS)

    Gonzalez-Mestres, L.; Perret-Gallix, D.

    1988-11-01

    A comprehensive introduction to cryogenic detector developments for particle physics is presented, covering conventional detectors cooled to low temperature (scintillators and semiconductors), superconductive and thermal sensitive devices, as well as the basics of cold electronics. After giving a critical overview of current work, we elaborate on possible new ways for further improvements and briefly evaluate the feasibility of the main proposed applications

  3. Bed system performance in helium circulation mode

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yean Jin; Jung, Kwang Jin; Ahn, Do Hee; Chung, Hong Suk [UST, Daejeon (Korea, Republic of); Kang, Hee Suk [KAERI, Daejeon (Korea, Republic of); Yun, Sei Hun [NFRI, Deajeon (Korea, Republic of)

    2016-05-15

    As a part of the International Thermonuclear Experimental Reactor (ITER) Project, We have conducted an experiment for storing hydrogen to depleted uranium and zirconium cobalt. The helium blanket effect has been observed in experiments using metal hydrides. The collapse of the hydrogen isotopes are accompanied by the decay heat and helium-3. Helium-3 dramatically reduces the hydrogen isotope storage capacity by surrounding the metal. This phenomenon is called a helium blanket effect. In addition the authors are working on the recovery and removal techniques of helium-3. In this paper, we discuss the equipment used to test the helium blanket effect and the results of a helium circulation experiment. The helium-3 produced surrounds the storage material surface and thus disturbs the reaction of the storage material and the hydrogen isotope. Even if the amount of helium-3 is small, the storage capacity of the SDS bed significantly drops. This phenomenon is the helium blanket effect. To resolve this phenomenon, a circulating loop was introduced. Using a circulating system, helium can be separated from the storage material. We made a helium loop that includes a ZrCo bed. Then using a metal bellows pump, we tested the helium circulation.

  4. Investigation on fabrication and positioning of cryogenic shell laser fusion targets. Annual report, October 1, 1977--November 30, 1978

    International Nuclear Information System (INIS)

    Kim, K.

    1978-01-01

    The research has been directed toward fabrication and positioning of cryogenic shell laser fusion targets, with particular emphasis on the development of a scheme which would allow for continuous fabrication, inspection, and delivery of the targets. Specifically, progress has been made in each of the following areas: (1) fabrication of a uniform layer of solid DT inside a glass microshell using a combination of helium gas jets and a heater wire; (2) levitation-freezing of a DT-filled glass microshell as a method for fabricating and positioning a cryogenic shell target; (3) a target fabrication system intended for continuous fabrication, inspection, and delivery of cryogenic targets; and (4) development of diagnostics for inspection, recording, and analysis of a solid DT layer inside a glass microshell, and for observing the parameters controlling the target freezing process

  5. Commissioning of the Cryogenic System for the ATLAS Superconducting Magnets

    CERN Document Server

    Delruelle, N; Bradshaw, T; Haug, F; ten Kate, H H J; Passardi, Giorgio; Pengo, R; Pezzetti, M; Pirotte, O; Rochford, J

    2006-01-01

    The paper describes the test results of the helium cryoplant for the superconducting magnets of the ATLAS particle detector at CERN. It consists of two refrigerators used in common by all the magnets and of two proximity cryogenic systems (PCS) interfacing respectively the toroids and the central solenoid. Emphasis is given to the commissioning of the refrigerators: the main unit of 6 kW equivalent capacity at 4.5 K and the thermal shield refrigerator providing 20 kW between 40 K and 80 K. The first unit is used for refrigeration at 4.5 K and for the cooling of three sets of 20 kA current leads, while the second one provides, in addition to the 20 kW refrigeration of the thermal shields, 60 kW for the cool-down to 100 K of the 660 ton cold mass of the magnets. The tests, carried out with the equipment in the final underground configuration, are extended to the PCS that includes the large liquid helium centrifugal pumps (each providing 1.2 kg/s) for forced-flow cooling of the magnets and the complex distributi...

  6. Construction of cryogenic testing system and tensile deformation behavior of AISI 300 series stainless steels at cryogenic temperatures

    International Nuclear Information System (INIS)

    Lee, H.M.; Nahm, S.H.; Huh, Y.H.; Lee, J.J.; Bahng, G.W.

    1990-01-01

    For practical application of cryogenic engineering, development and characterization of structural materials for use at low temperatures are essential. For these purposes, a system for mechanical testing at liquid helium temperatures was developed and it was shown that the precision and accuracy of the system met the requirements of standards for materials testing machines. Using this system, tensile deformation behavior of AISI 304,316 and 310S austenitic stainless steels at cryogenic temperatures was investigated. Tests were conducted on round, tensile specimens having a 6.25mm diameter at 4,77, and 295 K and loading rate was 0.5mm/min. Serrations were observed in all alloys at 4 K. The stress-displacement curves at 77 and 4 K showed different tendency from those at 298 K. As the testing temperature decreased, ultimate strengths of 304 and 316 were largely increased compared to the increase of yield strengths, but the increase of ultimate strength of 310S was almost the same to that of yield strength. Type 310S had the highest yield strength and the lowest tensile strength at all temperatutes. These tensile characteristics were considered to be strongly affected by austenite stability.(Author)

  7. Pierre Gorce working on a helium pump.

    CERN Multimedia

    1975-01-01

    This type of pump was designed by Mario Morpurgo, to circulate liquid helium in superconducting magnets wound with hollow conductors. M. Morpurgo, Design and construction of a pump for liquid helium, CRYIOGENICS, February 1977, p. 91

  8. Convective mixing in helium white dwarfs

    International Nuclear Information System (INIS)

    Vauclair, G.; Fontaine, G.

    1979-01-01

    The conditions under which convective mixing episodes take place between the helium envelopes and the underlying carbon layers in helium-rich white dwarfs are investigated. It is found that, for essentially any value of the initial helium content less than the maximum mass a helium convection zone can have, mixing does occur, and leads, in the vast majority of cases, to an almost pure carbon superficial composition. Mixing products that show only traces of carbon while retaining helium-dominated envelopes are possible only if the initial helium content is quite close to the maximum possible mass of the helium convection zone. In the presence of turbulence, this restriction could be relaxed, however, and the helium-rich lambda4670 stars may possibly be explained in this fashion

  9. Search for new physics at LEP 2

    CERN Document Server

    Gross, Eilam

    1997-01-01

    The results of the search for Higgs bosons, Charginos, Neutralinos, Sleptons, Squarks and light Gravitinos with the LEP accelerator at 130-172 GeV center-of-mass energy are briefly described. Prospects for Standard Model Higgs search at higher center-of-mass energies are also given.

  10. W Boson Polarisation at LEP2

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Couchman, J.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krieger, P.; von Krogh, J.; Kruger, K.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Masetti, G.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rosati, S.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schoerner-Sadenius, Thomas; Schroder, Matthias; Schumacher, M.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2004-01-01

    Elements of the spin density matrix for W bosons in e+e- -> W+W- -> qqln events are measured from data recorded by the OPAL detector at LEP. This information is used calculate polarised differential cross-sections and to search for CP-violating effects. Results are presented for W bosons produced in e+e- collisions with centre-of-mass energies between 183 GeV and 209 GeV. The average fraction of W bosons that are longitudinally polarised is found to be (23.9 +- 2.1 +- 1.1)% compared to a Standard Model prediction of (23.9 +- 0.1)%. All results are consistent with CP conservation.

  11. Search for Radions at LEP2

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Masetti, G.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, Niels T.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, Matthias; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2005-01-01

    A new scalar resonance, called the radion, with couplings to fermions and bosons similar to those of the Higgs boson, is predicted in the framework of Randall-Sundrum models, proposed solutions to the hierarchy problem with one extra dimension. An important distinction between the radion and the Higgs boson is that the radion would couple directly to gluon pairs, and in particular its decay products would include a significant fraction of gluon jets. The radion had the same quantum numbers as the Standard Model (SM) Higgs boson, and therefore they can mix, with the resulting mass eigenstates having properties different from those of the SM Higgs boson. Existing searches for the Higgs boson are sensitive to the possible production and decay of radions and Higgs bosons in these models. For the first time, searches for the SM Higgs boson and flavour-independent and decay-mode independent searches for a neutral Higgs boson are used in combination to explore the parameter space of the Randall-Sundrum model. In the...

  12. Search for radions at LEP2

    International Nuclear Information System (INIS)

    Abbiendi, G.; Ainsley, C.; Akesson, P.F.

    2005-01-01

    A new scalar resonance, called the radion, with couplings to fermions and bosons similar to those of the Higgs boson, is predicted in the framework of Randall-Sundrum models, proposed solutions to the hierarchy problem with one extra dimension. An important distinction between the radion and the Higgs boson is that the radion would couple directly to gluon pairs, and in particular its decay products would include a significant fraction of gluon jets. The radion has the same quantum numbers as the Standard Model (SM) Higgs boson, and therefore they can mix, with the resulting mass eigenstates having properties different from those of the SM Higgs boson. Existing searches for the Higgs bosons are sensitive to the possible production and decay of radions and Higgs bosons in these models. For the first time, searches for the SM Higgs boson and flavour-independent and decay-mode independent searches for a neutral Higgs boson are used in combination to explore the parameter space of the Randall-Sundrum model. In the dataset recorded by the OPAL experiment at LEP, no evidence for radion or Higgs particle production was observed in any of those searches at centre-of-mass energies up to 209 GeV. The results are used to set limits on the radion and Higgs boson masses. For all parameters of the Randall-Sundrum model, the data exclude masses below 58 GeV for the mass eigenstate which becomes the Higgs boson in the no-mixing limit

  13. Fermion pair physics at LEP2

    International Nuclear Information System (INIS)

    Georgios, Anagnostou

    2004-01-01

    Combined measurements of the 4 LEP collaborations for the fermion pair processes e + e - →f anti f are presented. The results show no significant deviations when compared with the Standard Model predictions and are used to set limits on contact interactions, Z' gauge bosons and low scale gravity models with large extra dimensions. (orig.)

  14. Main improvements of LHC Cryogenics Operation during Run 2 (2015-2018)

    Science.gov (United States)

    Delprat, L.; Bradu, B.; Brodzinski, K.; Ferlin, G.; Hafi, K.; Herblin, L.; Rogez, E.; Suraci, A.

    2017-12-01

    After the successful Run 1 (2010-2012), the LHC entered its first Long Shutdown period (LS1, 2013-2014). During LS1 the LHC cryogenic system went under a complete maintenance and consolidation program. The LHC resumed operation in 2015 with an increased beam energy from 4 TeV to 6.5 TeV. Prior to the new physics Run 2 (2015-2018), the LHC was progressively cooled down from ambient to the 1.9 K operation temperature. The LHC has resumed operation with beams in April 2015. Operational margins on the cryogenic capacity were reduced compared to Run 1, mainly due to the observed higher than expected electron-cloud heat load coming from increased beam energy and intensity. Maintaining and improving the cryogenic availability level required the implementation of a series of actions in order to deal with the observed heat loads. This paper describes the results from the process optimization and update of the control system, thus allowing the adjustment of the non-isothermal heat load at 4.5 - 20 K and the optimized dynamic behaviour of the cryogenic system versus the electron-cloud thermal load. Effects from the new regulation settings applied for operation on the electrical distribution feed-boxes and inner triplets will be discussed. The efficiency of the preventive and corrective maintenance, as well as the benefits and issues of the present cryogenic system configuration for Run 2 operational scenario will be described. Finally, the overall availability results and helium management of the LHC cryogenic system during the 2015-2016 operational period will be presented.

  15. Helium localization around the microscopic impurities embedded to liquid helium

    International Nuclear Information System (INIS)

    Gordon, E.B.; Shestakov, A.F.

    2000-01-01

    The structure and properties of the environment round the impurity atoms (Im) embedded in liquid helium are considered. It is shown that there are two qualitatively different types of structure of the He atom layer next to Im - attraction and repulsion structures. For the center attraction structure (strong Im-He interaction) the Im-He separation is longer than the equilibrium one for the pair Im-He potential, and the density and localization of He atoms are higher than in the bulk. It this case the He atom content in the layer, n, is almost independent of applied pressure. In the repulsion structure realized for alkaline metal atoms the Im-He separation is shorter than the equilibrium one and the density is lower than in the helium bulk. At T approx 1 K occupied are several states with different n and their energies differ only by approx 0.1 K, an increase in pressure resulting in a considerable reduction of n. The optical and EPR spectra of the atoms embedded to liquid and solid helium are interpreted on the basis of the analysis carried out. A simple model is proposed to evaluate the helium surroundings characteristics from the experimental pressure dependences of atomic line shifts in the absorption and emission spectra. The attraction structures in 3 He - 4 He mixtures are suggested to be highly enriched by 4 He atoms which the repulsion structures - by 3 He atoms. a possibility for existence of phase transitions in helium shells surrounding impurity atoms is considered

  16. Helium behaviour in aluminium under hydrostatic pressure

    International Nuclear Information System (INIS)

    Sokurskij, Yu.N.; Tebus, V.N.; Zudilin, V.A.; Tumanova, G.M.

    1989-01-01

    Effect of hydrostatic compression on equilibrium helium bubbles in low aluminium-lithium alloy irradiated in reactor at 570 K is investigated. Measurements of hydrostatic density and electron-microscopic investigations have shown, that application of up to 2 GPa pressure reduces equilibrium size of helium bubbles and reduces helium swelling. Kinetics and thermodynamics of the process are considered with application of 'rigid sphere' equation which describes helium state in bubbles

  17. Explosive helium burning in white dwarf stars

    Energy Technology Data Exchange (ETDEWEB)

    Khokhlov, A.M. (AN SSSR, Moscow. Astronomicheskij Sovet)

    1984-04-01

    Helium burning kinetics in white dwarfs has been considered at constant temperatures T >= 10/sup 9/ K and densities rho >10/sup 5/ g/cm/sup 3/. It is found, that helium detonation in white dwarfs does not lead to formation of light (A < 56) elements. Thus, helium white dwarf model for supernova 1 is inconsistent with observations.

  18. Clustering of Helium Atoms at a ½

    NARCIS (Netherlands)

    Berg, F. v.d.; Heugten, W. v.; Caspers, L.M.; Veen, A. v.; Hosson, J.Th.M. de

    1977-01-01

    Atomistic calculations on a ½<111>{110} edge dislocation show a restricted tendency of clustering of helium atom along this dislocation. Clusters with up to 4 helium atoms have been studied. A cluster with 3 helium proved to be most stable.

  19. Development of helium transfer coupling of 1 MW-class HTS motor for podded ship propulsion system

    Energy Technology Data Exchange (ETDEWEB)

    Kosuge, Eiji; Gocho, Yoshitsugu; Okumura, Kagao; Yamaguchi, Mitsugi [JapaneseSuperconductivity Organization, 135-8533, Tokyo (Japan); Umemoto, Katsuya; Aizawa, Kiyoshi; Yokoyama, Minoru; Takao, Satoru, E-mail: gocho@jso--new-scm.co.j [Kawasaki Heavy Industries LTD., 673-8666, Hyogo (Japan)

    2010-06-01

    Research and development of 1 MW superconducting motor are being made aiming at the efficiency improvement for the podded type ship propulsion. The basic machine configuration is similar to steam turbine generators, having a rotating horizontal shaft. As for the motor composed of rotating superconducting field, one of the most critical issues is to provide a technically viable helium transfer coupling (HTC). The field winding of 1 MW motor is cooled with cryogenic helium gas. The HTC needs to supply the cryogenic helium gas with an appropriate flow rate from the stationary part to the rotating field winding region through a hollowed shaft in order not to lose superconducting state of the winding. A full size prototype of HTC was developed prior to the actual one to demonstrate its technical acceptability. The fundamental data with regard to the supply of the refrigerated helium gas were successfully obtained at the rated speed. This work has been supported by New Energy, and Industrial Technology Development Organization (NEDO).

  20. Leak testing of cryogenic components — problems and solutions

    Science.gov (United States)

    Srivastava, S. P.; Pandarkar, S. P.; Unni, T. G.; Sinha, A. K.; Mahajan, K.; Suthar, R. L.

    2008-05-01

    A prototype of Cold Neutron Source (CNS) for Dhruva Reactor is being manufactured at Centre for Design and Manufacture (CDM), BARC, Mumbai for validating the mechanical and thermal engineering design aspects, besides checking the integrity of all joints and components at low temperature, 77K. Task of a Cold Neutron Source is to generate cold neutrons by cooling down the thermal neutrons, which are originally produced in a nuclear research reactor. The complete Cold Neutron Source system comprises a complex arrangement of moderator pot, transfer line (piping), pumps, refrigerators, storage tanks, a heat exchanger and associated controls and instrumentation. The heart of the system is moderator pot in which water (moderator) is cooled down by Liquid Nitrogen (LN2) being circulated through an annular cavity machined on the walls of the pot. Transfer lines for LN2 basically consist of two concentric Stainless Steel flexible pipes, which are joined to the inlet and outlet Aluminium tubes of the moderator pot through transition joints. Leak in any component may result in loss of liquid Nitrogen, degradation of vacuum, which in turn may affect the heat removal efficiency of the source. Hence, leak testing was considered a very important quality control tool and all joints and components were subjected to helium leak test using mass spectrometer leak detector (MSLD) at cryogenic temperature. During one of the earlier experiments, flow of LN2 through inner flexible pipe of the transfer line resulted in rise of pressure in the vacuum annulus and sweating on the outer flexible pipe. After investigations it was found that large thermal stress compounded with mechanical stress resulted in cracks in the inner pipe. Accordingly design was modified to get leak proof transfer line assembly. Further, during leak testing of thin wall moderator pot, gross leak was observed on the outer jacket welded joint. Leak was so large that even a small amount of Helium gas in the vicinity of the

  1. A cryogen-free low temperature scanning tunneling microscope capable of inelastic electron tunneling spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuai; Huang, Di [State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (MOE), and Department of Physics, Fudan University, Shanghai 200433 (China); Wu, Shiwei, E-mail: swwu@fudan.edu.cn [State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (MOE), and Department of Physics, Fudan University, Shanghai 200433 (China); Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433 (China)

    2016-06-15

    The design and performance of a cryogen-free low temperature scanning tunneling microscope (STM) housed in ultrahigh vacuum (UHV) are reported. The cryogen-free design was done by directly integrating a Gifford-McMahon cycle cryocooler to a Besocke-type STM, and the vibration isolation was achieved by using a two-stage rubber bellow between the cryocooler and a UHV-STM interface with helium exchange gas cooling. A base temperature of 15 K at the STM was achieved, with a possibility to further decrease by using a cryocooler with higher cooling power and adding additional low temperature stage under the exchange gas interface. Atomically sharp STM images and high resolution dI/dV spectra on various samples were demonstrated. Furthermore, we reported the inelastic tunneling spectroscopy on a single carbon monoxide molecule adsorbed on Ag(110) surface with a cryogen-free STM for the first time. Being totally cryogen-free, the system not only saves the running cost significantly but also enables uninterrupted data acquisitions and variable temperature measurements with much ease. In addition, the system is capable of coupling light to the STM junction by a pair of lens inside the UHV chamber. We expect that these enhanced capabilities could further broaden our views to the atomic-scale world.

  2. A cryogen-free low temperature scanning tunneling microscope capable of inelastic electron tunneling spectroscopy.

    Science.gov (United States)

    Zhang, Shuai; Huang, Di; Wu, Shiwei

    2016-06-01

    The design and performance of a cryogen-free low temperature scanning tunneling microscope (STM) housed in ultrahigh vacuum (UHV) are reported. The cryogen-free design was done by directly integrating a Gifford-McMahon cycle cryocooler to a Besocke-type STM, and the vibration isolation was achieved by using a two-stage rubber bellow between the cryocooler and a UHV-STM interface with helium exchange gas cooling. A base temperature of 15 K at the STM was achieved, with a possibility to further decrease by using a cryocooler with higher cooling power and adding additional low temperature stage under the exchange gas interface. Atomically sharp STM images and high resolution dI/dV spectra on various samples were demonstrated. Furthermore, we reported the inelastic tunneling spectroscopy on a single carbon monoxide molecule adsorbed on Ag(110) surface with a cryogen-free STM for the first time. Being totally cryogen-free, the system not only saves the running cost significantly but also enables uninterrupted data acquisitions and variable temperature measurements with much ease. In addition, the system is capable of coupling light to the STM junction by a pair of lens inside the UHV chamber. We expect that these enhanced capabilities could further broaden our views to the atomic-scale world.

  3. Cryogenic Hazard at ESS – strategy, safety studies and lessons learned

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    The European Spallation Source (ESS) is building a linear accelerator (linac) aiming at delivering a 2 GeV proton beam on a tungsten target wheel at 5 MW nominal power. The entire accelerator will be housed in an underground tunnel and will be fully operational by 2023. The superconducting section of the linac is composed of 21 High Beta cryomodules, 9 Medium Beta cryomodules and 13 Spoke cryomodules, as well as a Cryogenic Distribution System (CDS) that will be provided with liquid helium. A total of 146 superconducting radio frequency (SRF) cavities operating at 2 K will be housed in those cryomodules. Additionally, cryogenic fluids will also be used for the cold hydrogen moderator surrounding the target as well as for several neutron instruments. In order to achieve a proper cooling, different facilities are being built to house the future cryogenic installation and therefore will be subject to Oxygen Deficiency Hazard (ODH). In order to address cryogenic safety issues ESS wide, a long-term strategy has ...

  4. Performance of the JT-60SA cryogenic system under pulsed heat loads during acceptance tests

    Science.gov (United States)

    Hoa, C.; Bonne, F.; Roussel, P.; Lamaison, V.; Girard, S.; Fejoz, P.; Goncalves, R.; Vallet, J. C.; Legrand, J.; Fabre, Y.; Pudys, V.; Wanner, M.; Cardella, A.; Di Pietro, E.; Kamiya, K.; Natsume, K.; Ohtsu, K.; Oishi, M.; Honda, A.; Kashiwa, Y.; Kizu, K.

    2017-12-01

    The JT-60SA cryogenic system a superconducting tokamak currently under assembly at Naka, Japan. After one year of commissioning, the acceptance tests were successfully completed in October 2016 in close collaboration with Air Liquide Advanced Technologies (ALaT), the French atomic and alternative energies commission (CEA), Fusion for Energy (F4E) and the Quantum Radiological Science and Technology (QST). The cryogenic system has several cryogenic users at various temperatures: the superconducting magnets at 4.4 K, the current leads at 50 K, the thermal shields at 80 K and the divertor cryo-pumps at 3.7 K. The cryogenic system has an equivalent refrigeration power of about 9.5 kW at 4.5 K, with peak loads caused by the nuclear heating, the eddy currents in the structures and the AC losses in the magnets during cyclic plasma operation. The main results of the acceptance tests will be reported, with emphasis on the management of the challenging pulsed load operation using a liquid helium volume of 7 m3 as a thermal damper.

  5. Thermal and structural analysis of a cryogenic conduction cooling system for a HTS NMR magnet

    Energy Technology Data Exchange (ETDEWEB)

    In, Se Hwan; Hong, Yong Jun; Yeom, Han Kil; Ko, Hyo Bong; Park, Seong Je [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2016-03-15

    The superconducting NMR magnets have used cryogen such as liquid helium for their cooling. The conduction cooling method using cryocoolers, however, makes the cryogenic cooling system for NMR magnets more compact and user-friendly than the cryogen cooling method. This paper describes the thermal and structural analysis of a cryogenic conduction cooling system for a 400 MHz HTS NMR magnet, focusing on the magnet assembly. The highly thermo-conductive cooling plates between HTS double pancake coils are used to transfer the heat generated in coils, namely Joule heating at lap splice joints, to thermal link blocks and finally the cryocooler. The conduction cooling structure of the HTS magnet assembly preliminarily designed is verified by thermal and structural analysis. The orthotropic thermal properties of the HTS coil, thermal contact resistance and radiation heat load are considered in the thermal analysis. The thermal analysis confirms the uniform temperature distribution for the present thermal design of the NMR magnet within 0.2 K. The mechanical stress and the displacement by the electromagnetic force and the thermal contraction are checked to verify structural stability. The structural analysis indicates that the mechanical stress on each component of the magnet is less than its material yield strength and the displacement is acceptable in comparison with the magnet dimension.

  6. Linear Model-Based Predictive Control of the LHC 1.8 K Cryogenic Loop

    CERN Document Server

    Blanco-Viñuela, E; De Prada-Moraga, C

    1999-01-01

    The LHC accelerator will employ 1800 superconducting magnets (for guidance and focusing of the particle beams) in a pressurized superfluid helium bath at 1.9 K. This temperature is a severely constrained control parameter in order to avoid the transition from the superconducting to the normal state. Cryogenic processes are difficult to regulate due to their highly non-linear physical parameters (heat capacity, thermal conductance, etc.) and undesirable peculiarities like non self-regulating process, inverse response and variable dead time. To reduce the requirements on either temperature sensor or cryogenic system performance, various control strategies have been investigated on a reduced-scale LHC prototype built at CERN (String Test). Model Based Predictive Control (MBPC) is a regulation algorithm based on the explicit use of a process model to forecast the plant output over a certain prediction horizon. This predicted controlled variable is used in an on-line optimization procedure that minimizes an approp...

  7. Development of a Cryogenic Radiation Detector for Mapping Radio Frequency Superconducting Cavity Field Emissions

    CERN Document Server

    Dotson, Danny W

    2005-01-01

    There is a relationship between field emissions in a Super Conducting RF cavity and the production of radiation (mostly X-rays). External (room temperature) detectors are shielded from the onset of low energy X-rays by the vacuum and cryogenic stainless steel module walls. An internal measuring system for mapping field emissions would assist scientists and engineers in perfecting surface deposition and acid washing module surfaces. Two measurement systems are undergoing cryogenic testing at JLab. One is an active CsI photodiode array and the second is an X-ray film camera. The CsI array has operated sucessfully in a cavity in liquid Helium but saturated at higher power due to scattering in the cavity. A shield with an aperature similar to the X-ray film detector is being designed for the next series of tests which will be completed before PAC-05.

  8. Evaluation Of Silicon Diodes As IN-SITU Cryogenic Field Emission Detectors For SRF Cavity Development

    International Nuclear Information System (INIS)

    Palczewski, Ari; Geng, Rongli

    2012-01-01

    We performed in-situ cryogenic testing of four silicon diodes as possible candidates for field emission (FE) monitors of superconducting radio frequency (SRF) cavities during qualification testing and in accelerator cryo-modules. We evaluated diodes from 2 companies - from Hamamatsu corporation model S1223-01; and from OSI Optoelectronics models OSD35-LR-A, XUV-50C, and FIL-UV20. The measurements were done by placing the diodes in superfluid liquid helium near the top of a field emitting 9-cell cavity during its vertical test. For each diode, we will discuss their viability as a 2K cryogenic detector for FE mapping of SRF cavities and the directionality of S1223-01 in such environments. We will also present calibration curves between the diodes and JLab's standard radiation detector placed above the Dewar's top plate.

  9. The Mirror Fusion Test Facility cryogenic system: Performance, management approach, and present equipment status

    International Nuclear Information System (INIS)

    Slack, D.S.; Chronis, W.C.

    1987-01-01

    The cryogenic system for the Mirror Fusion Test Facility (MFTF) is a 14-kW, 4.35-K helium refrigeration system that proved to be highly successful and cost-effective. All operating objectives were met, while remaining within a few percent of initial cost and schedule plans. The management approach used in MFTF allowed decisions to be made quickly and effectively, and it helped keep costs down. Manpower levels, extent and type of industrial participation, key aspects of subcontractor specifications, and subcontractor interactions are reviewed, as well as highlights of the system tests, operation, and present equipment status. Organizations planning large, high-technology systems may benefit from this experience with the MFTF cryogenic system

  10. Cryogenic analysis of forced-cooled, superconducting TF magnets for compact tokamak reactors

    International Nuclear Information System (INIS)

    Kerns, J.A.; Slack, D.S.; Miller, J.R.

    1988-01-01

    Current designs for compact tokamak reactors require the toroidal- field (TF) superconducting magnets to produce fields from 10 to 15 T at the winding pack, using high-current densities to high nuclear heat loads (greater than 1 kW/coil in some instances), which are significantly greater than the conduction and radiation heat loads for which cryogenic systems are usually designed. A cryogenic system for the TF winding pack for two such tokamak designs has been verified by performing a detailed, steady-state heat-removal analysis. Helium properties along the forced-cooled conductor flow path for a range of nuclear heat loads have been calculated. The results and implications of this analysis are presented. 12 refs., 6 figs

  11. Muonium and neutral muonic helium

    International Nuclear Information System (INIS)

    Orth, H.

    1981-01-01

    In this brief article the current status on muonium spectroscopy with emphasis on recent developments will be summarized. The experimental and theoretical progress of the muonic helium atom will be reviewed. Future directions in this field of research will be discussed. (orig./HSI)

  12. Electric response in superfluid helium

    Czech Academy of Sciences Publication Activity Database

    Chagovets, Tymofiy

    2016-01-01

    Roč. 488, May (2016), s. 62-66 ISSN 0921-4526 R&D Projects: GA ČR GP13-03806P Institutional support: RVO:68378271 Keywords : superfluid helium * electric response * second sound * ions in He II Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.386, year: 2016

  13. Production of negative helium ions

    International Nuclear Information System (INIS)

    Toledo, A.S. de; Sala, O.

    1977-01-01

    A negative helium ion source using potassium charge exchange vapor has been developed to be used as an injector for the Pelletron accelerator. 3 He and α beam currents of up to 2μA have been extracted with 75% particle transmission through the machine [pt

  14. Cryogenic systems for detectors and particle accelerators

    International Nuclear Information System (INIS)

    Sondericker, J.H.

    1988-01-01

    It's been one hundred years since the first successful experiments were carried out leading to the liquefaction of oxygen which birthed the field of cryogenics and about sixty years since cryogenics went commercial. Originally, cryogenics referred to the technology and art of producing low temperatures but today the definition adopted by the XII Congress of the International Institute of Refrigeration describes cryogenics as the study of phenomena, techniques, and concepts occurring at our pertaining to temperatures below 120 K. Modern acceptance of the importance and use of cryogenic fluids continues to grow. By far, the bulk of cryogenic products are utilized by industry for metal making, agriculture, medicine, food processing and as efficient storage of fuels. Cryogenics has found many uses in the scientific community as well, enabling the development of ultra low noise amplifiers, fast cold electronics, cryopumped ultra high vacuums, the production of intense magnetic fields and low loss power transmission through the sue of cryogenically cooled superconductors. High energy physic research has been and continues to use cryogenic hardware to produce liquids used as detector targets and to produce refrigeration necessary to cool superconducting magnets to design temperature for particle accelerator applications. In fact, today's super accelerators achieve energies that would be impossible to reach with conventional copper magnets, demonstrating that cryogenics has become an indispensable ingredient in today's scientific endeavors

  15. Simplicity works for superfluid helium

    International Nuclear Information System (INIS)

    Bowley, Roger

    2000-01-01

    The famous philosopher Karl Popper once said that ''science is the art of systematic oversimplification''. Indeed, when faced with a new puzzle the trick is to simplify it without losing the essential physics - something that is easier said than done. However, this approach has paid off recently in low-temperature physics. Last year Richard Packard, Seamus Davis and co-workers at the University of California at Berkeley encountered a puzzling new phenomenon in superfluid helium-3, a quantum fluid that remains a liquid close to absolute zero and exhibits unusual properties such as the ability to flow without friction (A Machenkov et al. 1999 Phys. Rev. Lett. 83 3860). Previous experiments had revealed that certain effects in liquid helium are analogous to effects observed in superconductors, materials that lose all resistance to electric current at low temperatures. When the Berkeley researchers connected two reservoirs of superfluid helium-3, the superfluid flowed back and forth through apertures that formed a ''weak link'' between the two containers. This behaviour is similar to the oscillatory current of electrons that can flow across an insulating gap separating two superconductors - a device that is known as a Josephson junction. What was puzzling about the Berkeley results was that the helium-3 had two different stable configurations, both of which behaved in an unconventional way compared with a Josephson junction. This puzzle has now been solved independently by Sidney Yip at the National Center for Theoretical Sciences in Taiwan, and by Janne Viljas and Erkki Thuneberg at the Helsinki University of Technology in Finland (Phys. Rev. Lett. 1999 83 3864 and 3868). In this article the author describes the latest research on superfluid helium. (UK)

  16. Simplicity works for superfluid helium

    Energy Technology Data Exchange (ETDEWEB)

    Bowley, Roger [University of Nottingham, Nottingham (United Kingdom)

    2000-02-01

    The famous philosopher Karl Popper once said that ''science is the art of systematic oversimplification''. Indeed, when faced with a new puzzle the trick is to simplify it without losing the essential physics - something that is easier said than done. However, this approach has paid off recently in low-temperature physics. Last year Richard Packard, Seamus Davis and co-workers at the University of California at Berkeley encountered a puzzling new phenomenon in superfluid helium-3, a quantum fluid that remains a liquid close to absolute zero and exhibits unusual properties such as the ability to flow without friction (A Machenkov et al. 1999 Phys. Rev. Lett. 83 3860). Previous experiments had revealed that certain effects in liquid helium are analogous to effects observed in superconductors, materials that lose all resistance to electric current at low temperatures. When the Berkeley researchers connected two reservoirs of superfluid helium-3, the superfluid flowed back and forth through apertures that formed a ''weak link'' between the two containers. This behaviour is similar to the oscillatory current of electrons that can flow across an insulating gap separating two superconductors - a device that is known as a Josephson junction. What was puzzling about the Berkeley results was that the helium-3 had two different stable configurations, both of which behaved in an unconventional way compared with a Josephson junction. This puzzle has now been solved independently by Sidney Yip at the National Center for Theoretical Sciences in Taiwan, and by Janne Viljas and Erkki Thuneberg at the Helsinki University of Technology in Finland (Phys. Rev. Lett. 1999 83 3864 and 3868). In this article the author describes the latest research on superfluid helium. (UK)

  17. Experimental study on the thermal hydraulic performance of plate-fin heat exchangers for cryogenic applications

    Science.gov (United States)

    Jiang, Qingfeng; Zhuang, Ming; Zhang, Qiyong; Zhu, Zhigang; Geng, Maofei; Sheng, Linhai; Zhu, Ping

    2018-04-01

    Efficient and compact plate-fin heat exchangers are critical for large-scale helium liquefaction/refrigeration systems as they constitute major part in the cold box. This study experimentally explores the heat transfer and pressure drop behaviors of helium gas at low temperature in four types of plate-fin channels, namely offset-strip and perforated fins, with different geometrical parameters. A series of cryogenic experiments at approximately liquid nitrogen temperature are carried out to measure the Colburn j factors and Fanning friction f factors with a wide range of Reynolds number. Besides, to reveal the performance variations under different operating temperatures, comparative experiments respectively conducted at room temperature and liquid nitrogen temperature are implemented. The results show that in comparison with the performance data at room temperature, most of j factors are relatively smaller perhaps because the lower aluminum thermal conductivity and higher Prandtl Number at low temperature. Meanwhile, the f factors corresponding to cryogenic conditions exhibit slightly larger even though the core pressure drops show considerable reductions. In contrast to the calculated results from the frequently-used performance curves (Chen and Shen, 1993), the Root Mean Squared Errors of j and f values are correlated within 8.38% and 6.97% for one perforated fin core, 41.29% and 34.97% for three OSF cores, respectively. For OSFs, further comparisons with the previous empirical correlations from literatures are conducted to verify the accuracy of each correlation. Generally, most of the calculated results predict acceptably within the deviations of ±25% for the j factors, while the predicted results express relatively large deviations for the f factors. Therefore, it may be revealed that most of the existing correlations were not able to accurately predict the experimental data in consideration of the performance differences under realistic cryogenic operating

  18. Development of modular thermostatic vapour-cooled current leads for cryogenic service

    International Nuclear Information System (INIS)

    Blessing, H.; Lebrun, P.

    1983-01-01

    Cryogenic current leads cooled by helium vapour have been developed, built and tested. Their construction, based on standard electrolytic copper braids crimped at the ends, is such as to provide flexible cold terminations and make possible a modular design. The warm terminations combine electrical insulation, leak-tightness and integrated thermostatic valves controlling lead temperature and avoiding thermal run-away or ice build-up. After giving a detailed description of their construction, this report presents results of performance and reliability tests made on prototype units. (orig.)

  19. Cryogenic polarized-target facility. Progress report, July 1, 1981-June 30, 1982

    International Nuclear Information System (INIS)

    Gould, C.R.; Haase, D.G.

    1982-01-01

    The goal of this three-year research project is to build a cryogenically polarized target facility for measuring total neutron cross sections for polarized neutrons incident on polarized nuclei. The components of the system have been assembled at TUNL during the current contract period. These include the dilution-refrigerator support assembly, the dilution-refrigerator itself, the dewar, the beam line, the shielding cave for the neutron source, and the neutron-detector shield and rolling-cart assembly. The dilution refrigerator is presently undergoing testing at liquid-nitrogen and liquid-helium temperatures. Experiments with aluminum and copper targets are scheduled for the coming contract period

  20. Criterion for burn-up conditions in gas-cooled cryogenic current leads

    International Nuclear Information System (INIS)

    Bejan, A.; Cluss, E.M. Jr.

    1976-01-01

    Superconducting magnets are energized through helium vapour-cooled cryogenic current leads operating at high ratios of current to mass flow. The high current operation where lead temperature, runaway, and eventual burn-up are likely to occur is investigated. A simple criterion for estimating the burn-up operation conditions (current, mass flow) for a given lead geometry (cross-sectional area, length, heat exchanger area) is presented. This article stresses the role played by the available heat exchanger area in avoiding burn-up at high ratios of current to mass flow. (author)

  1. A generic pump/compressor design for circulation of cryogenic fluids

    International Nuclear Information System (INIS)

    Jasinski, T.; Honkonen, S.C.; Sixsmith, H.; Stacy, W.D.

    1986-01-01

    This paper describes the development of a second-generation centrifugal circulator for cryogenic fluids. The circulator is designed to operate over a wide range of flow rate and pressure rise and can be used for the pumping of liquid and compression of vapor at temperatures down to liquid helium (4 K). The machine incorporates self-acting gas journal bearings, a permanent magnet axial thrust bearing, and a variable speed induction motor drive to provide for reliable, maintenance-free operation. The paper provides design details of the pump. Calculated performance characteristics are also presented along with a general discussion regarding limitations of the present system

  2. Electromagnetic dampers for cryogenic applications

    Science.gov (United States)

    Brown, Gerald V.; Dirusso, Eliseo

    1988-01-01

    Cryogenic turbomachinery of the type used to pump high-pressure liquid hydrogen at -423 F and liquid oxygen at -297 F to the main engines of the Space Shuttle are subjected to lateral rotor vibrations from unbalance forces and transient loads. Conventional dampers which utilize viscous fluids such as lubricating oil cannot be used in turbopumps because the bearing components are filled with either liquid hydrogen or liquid oxygen, which have viscosity comparable to air and, therefore, are not effective in viscous dampers. Electromagentic dampers are currently being explored as a means of providing damping in cryogenic turbopumps because their damping effectiveness increases as temperature decreases and because they are compatible with the liquid hydrogen or liquid oxygen in the turbopumps.

  3. Precise Measurements of the Density and Critical Phenomena Near Phase Transitions in Liquid Helium

    Science.gov (United States)

    Yeh, Nai-Chang

    1997-01-01

    The first-year progress for the project of precise measurements of the density and critical phenomena of helium near phase transitions is summarized below: (1) completion of a cryogenic sample probe for the proposed measurements, and the rehabilitation of a designated laboratory at Caltech for this project; (2) construction and testing of a superconducting niobium cavity; (3) acquisition of one phase-locked-loop system for high-resolution frequency control and read- out; (4) setting up high-resolution thermometry (HRT) for temperature readout and control; (5) developing new approaches for calibrating the coefficient between the resonant frequency shift (delta f) and the helium density (rho), as well as for measuring the effect of gravity on T(sub lambda) to a much better precision; (6) programming of the interface control of all instruments for automatic data acquisition; and (7) improving data analyses and fitting procedures.

  4. Cryogenic moderator simulations: confronting reality

    International Nuclear Information System (INIS)

    Iverson, E. B.

    1999-01-01

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a spallation neutron source dedicated to materials research. Its three cryogenic methane moderators provide twelve neutron beams to fourteen instruments and test facilities. This report concerns ongoing activities for benchmarking our Monte Carlo model of the IPNS neutron generation system. This paper concentrates on the techniques (both experimental and calculational) used in such benchmarking activities

  5. Composite materials for cryogenic structures

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1978-01-01

    The paper is concerned with the composition, mechanical properties and capabilities of various types of composite materials for cryogenic structures. Attention is given to high-pressure plastic laminates, low-pressure plastic laminates, metal-matrix laminates, and aggregates (low-temperature concretes). The ability of these materials to match the strength and modulus of stainless steels suggests that their usage will substantially increase as alloying elements become scarce and more expensive

  6. Surface tension confined liquid cryogen cooler

    International Nuclear Information System (INIS)

    Castles, S.H.; Schein, M.E.

    1989-01-01

    A cryogenic cooler is described for use in craft such as launch, orbital and space vehicles subject to changes in orientation and conditions of vibration and weightlessness comprising: an insulated tank; a porous open celled sponge-like material disposed substantially throughout the contained volume of the insulated tank; a cryogenic fluid disposed within the sponge-like material; a cooling finger immersed in the cryogenic fluid, the finger extending from inside the insulated tank externally to an outside source such as an instrument detector for the purpose of transmitting heat from the outside source into the cryogenic fluid; means for filling the insulated tank with cryogenic fluid; and means for venting vaporized cryogenic fluid from the insulated tank

  7. HeREF-2003: Helium Refrigeration Techniques

    CERN Multimedia

    2003-01-01

    CERN Technical Training 2003: Learning for the LHC ! Theory, Technology, Maintenance and Control of Helium Refrigerators HeREF-2003 is a course in the framework of the 2002 Technical Training Programme, that will provide a complete introduction to Helium refrigeration, with a practical approach to theory, technology, maintenance and control of Helium refrigeration installations. Theoretical aspects and equations will be limited to a minimum. HeREF-2003 targets an audience of technicians and operators of Helium refrigeration plants at CERN, as well as physicists and engineers needing an overview of current Helium refrigeration techniques. HeREF-2003 will address, among other, issues related to component technology, installation maintenance, process control and Helium purity. A commented visit to a couple of CERN Helium refrigeration or liquefaction plants will also take place. Duration: 7 half days (4 mornings and 3 afternoons), 6-10 October, 2003 Cost per participant: 500.- CHF Language: Bilingual English...

  8. HeREF-2003 : Helium Refrigeration Techniques

    CERN Multimedia

    2003-01-01

    CERN Technical Training 2003: Learning for the LHC ! Theory, Technology, Maintenance and Control of Helium Refrigerators HeREF-2003 is a course in the framework of the 2002 Technical Training Programme, that will provide a complete introduction to Helium refrigeration, with a practical approach to theory, technology, maintenance and control of Helium refrigeration installations. Theoretical aspects and equations will be limited to a minimum. HeREF-2003 targets an audience of technicians and operators of Helium refrigeration plants at CERN, as well as physicists and engineers needing an overview of current Helium refrigeration techniques. HeREF-2003 will address, among other, issues related to component technology, installation maintenance, process control and Helium purity. A commented visit to a couple of CERN Helium refrigeration or liquefaction plants will also take place. • Duration: 7 half days (4 mornings and 3 afternoons), 6-10 October, 2003 • Cost per participant: 500.- CHF ...

  9. The evolution of cryogenic safety at Fermilab

    International Nuclear Information System (INIS)

    Stanek, R.; Kilmer, J.

    1992-12-01

    Over the past twenty-five years, Fermilab has been involved in cryogenic technology as it relates to pursuing experimentation in high energy physics. The Laboratory has instituted a strong cryogenic safety program and has maintained a very positive safety record. The solid commitment of management and the cryogenic community to incorporating safety into the system life cycle has led to policies that set requirements and help establish consistency for the purchase and installation of equipment and the safety analysis and documentation

  10. Model-based minimization algorithm of a supercritical helium loop consumption subject to operational constraints

    Science.gov (United States)

    Bonne, F.; Bonnay, P.; Girard, A.; Hoa, C.; Lacroix, B.; Le Coz, Q.; Nicollet, S.; Poncet, J.-M.; Zani, L.

    2017-12-01

    Supercritical helium loops at 4.2 K are the baseline cooling strategy of tokamaks superconducting magnets (JT-60SA, ITER, DEMO, etc.). This loops work with cryogenic circulators that force a supercritical helium flow through the superconducting magnets in order that the temperature stay below the working range all along their length. This paper shows that a supercritical helium loop associated with a saturated liquid helium bath can satisfy temperature constraints in different ways (playing on bath temperature and on the supercritical flow), but that only one is optimal from an energy point of view (every Watt consumed at 4.2 K consumes at least 220 W of electrical power). To find the optimal operational conditions, an algorithm capable of minimizing an objective function (energy consumption at 5 bar, 5 K) subject to constraints has been written. This algorithm works with a supercritical loop model realized with the Simcryogenics [2] library. This article describes the model used and the results of constrained optimization. It will be possible to see that the changes in operating point on the temperature of the magnet (e.g. in case of a change in the plasma configuration) involves large changes on the cryodistribution optimal operating point. Recommendations will be made to ensure that the energetic consumption is kept as low as possible despite the changing operating point. This work is partially supported by EUROfusion Consortium through the Euratom Research and Training Program 20142018 under Grant 633053.

  11. Quantitative method for measuring heat flux emitted from a cryogenic object

    Science.gov (United States)

    Duncan, R.V.

    1993-03-16

    The present invention is a quantitative method for measuring the total heat flux, and of deriving the total power dissipation, of a heat-fluxing object which includes the steps of placing an electrical noise-emitting heat-fluxing object in a liquid helium bath and measuring the superfluid transition temperature of the bath. The temperature of the liquid helium bath is thereafter reduced until some measurable parameter, such as the electrical noise, exhibited by the heat-fluxing object or a temperature-dependent resistive thin film in intimate contact with the heat-fluxing object, becomes greatly reduced. The temperature of the liquid helum bath is measured at this point. The difference between the superfluid transition temperature of the liquid helium bath surrounding the heat-fluxing object, and the temperature of the liquid helium bath when the electrical noise emitted by the heat-fluxing object becomes greatly reduced, is determined. The total heat flux from the heat-fluxing object is determined as a function of this difference between these temperatures. In certain applications, the technique can be used to optimize thermal design parameters of cryogenic electronics, for example, Josephson junction and infrared sensing devices.

  12. Quantitative method for measuring heat flux emitted from a cryogenic object

    International Nuclear Information System (INIS)

    Duncan, R.V.

    1993-01-01

    The present invention is a quantitative method for measuring the total heat flux, and of deriving the total power dissipation, of a heat-fluxing object which includes the steps of placing an electrical noise-emitting heat-fluxing object in a liquid helium bath and measuring the superfluid transition temperature of the bath. The temperature of the liquid helium bath is thereafter reduced until some measurable parameter, such as the electrical noise, exhibited by the heat-fluxing object or a temperature-dependent resistive thin film in intimate contact with the heat-fluxing object, becomes greatly reduced. The temperature of the liquid helum bath is measured at this point. The difference between the superfluid transition temperature of the liquid helium bath surrounding the heat-fluxing object, and the temperature of the liquid helium bath when the electrical noise emitted by the heat-fluxing object becomes greatly reduced, is determined. The total heat flux from the heat-fluxing object is determined as a function of this difference between these temperatures. In certain applications, the technique can be used to optimize thermal design parameters of cryogenic electronics, for example, Josephson junction and infrared sensing devices

  13. Use of the TACL [Thaumaturgic Automated Control Logic] system at CEBAF [Continuous Electron Beam Accelerator Facility] for control of the Cryogenic Test Facility

    International Nuclear Information System (INIS)

    Navarro, E.; Keesee, M.; Bork, R.; Grubb, C.; Lahti, G.; Sage, J.

    1989-01-01

    A logic-based control software system, called Thaumaturgic Automated Control Logic (TACL), is under development at the Continuous Electron Beam Accelerator Facility in Newport News, VA. The first version of the software was placed in service in November, 1987 for control of cryogenics during the first superconducting RF cavity tests at CEBAF. In August, 1988 the control system was installed at the Cryogenic Test Facility (CTF) at CEBAF. CTF generated liquid helium in September, 1988 and is now in full operation for the current round of cavity tests. TACL is providing a powerful and flexible controls environment for the operation of CTF. 3 refs

  14. The New Superfluid Helium Cryostats for the Short Straight Sections of the CERN Large Hadron Collider (LHC)

    CERN Document Server

    Cameron, W; Kurtyka, T; Parma, Vittorio; Renaglia, T; Rifflet, J M; Rohmig, P; Skoczen, Blazej; Tortschanoff, Theodor; Trilhe, P; Védrine, P; Vincent, D

    1998-01-01

    The lattice of the CERN Large Hadron Collider (LHC) contains 364 Short Straight Section (SSS) units, one in every 53 m long half-cell. An SSS consists of three major assemblies: the standard cryostat section, the cryogenic service module, and the jumper connection. The standard cryostat section of an SSS contains the twin aperture high-gradient superconducting quadrupole and two pairs of superconducting corrector magnets, operating in pressurized helium II at 1.9 K. Components for isolating cryostat insulation vacuum, and the cryogenic supply lines, have to be foreseen. Special emphasis is given to the design changes of the SSS following adoption of an external cryogenic supply line (QRL). A jumper connection connects the SSS to the QRL, linking all the cryogenic tubes necessary for the local full-cell cooling loop [at every second SSS]. The jumper is connected to one end of the standard cryostat section via the cryogenic service module, which also houses beam diagnostics, current feedthroughs, and instrument...

  15. Heat operated cryogenic electrical generator

    International Nuclear Information System (INIS)

    Fletcher, J.C.; Wang, T.C.; Saffren, M.M.; Elleman, D.D.

    1975-01-01

    An electrical generator useful for providing electrical power in deep space, is disclosed. The subject electrical generator utilizes the unusual hydrodynamic property exhibited by liquid helium as it is converted to and from a superfluid state to cause opposite directions of rotary motion for a rotor cell thereof. The physical motion of said rotor cell is employed to move a magnetic field provided by a charged superconductive coil mounted on the exterior of said cell. An electrical conductor is placed in surrounding proximity to said cell to interact with the moving magnetic field provided by the superconductive coil and thereby generate electrical energy. A heat control arrangement is provided for the purpose of causing the liquid helium to be partially converted to and from a superfluid state by being cooled and heated, respectively. (U.S.)

  16. Impulse approximation in solid helium

    International Nuclear Information System (INIS)

    Glyde, H.R.

    1985-01-01

    The incoherent dynamic form factor S/sub i/(Q, ω) is evaluated in solid helium for comparison with the impulse approximation (IA). The purpose is to determine the Q values for which the IA is valid for systems such a helium where the atoms interact via a potential having a steeply repulsive but not infinite hard core. For 3 He, S/sub i/(Q, ω) is evaluated from first principles, beginning with the pair potential. The density of states g(ω) is evaluated using the self-consistent phonon theory and S/sub i/(Q,ω) is expressed in terms of g(ω). For solid 4 He resonable models of g(ω) using observed input parameters are used to evaluate S/sub i/(Q,ω). In both cases S/sub i/(Q, ω) is found to approach the impulse approximation S/sub IA/(Q, ω) closely for wave vector transfers Q> or approx. =20 A -1 . The difference between S/sub i/ and S/sub IA/, which is due to final state interactions of the scattering atom with the remainder of the atoms in the solid, is also predominantly antisymmetric in (ω-ω/sub R/), where ω/sub R/ is the recoil frequency. This suggests that the symmetrization procedure proposed by Sears to eliminate final state contributions should work well in solid helium

  17. Liquid helium plant in Dubna

    International Nuclear Information System (INIS)

    Agapov, N.N.; Baldin, A.M.; Kovalenko, A.D.

    1995-01-01

    The liquid-helium cooling capacity installed at the Laboratory of High Energies is about 5 kw at a 4.5 K temperature level. It is provided with four industrial helium liquefiers of 1.6 kw/4.5 K each. They have been made by the Russian enterprise NPO GELYMASH and upgraded by the specialists of the Laboratory. The first one was put into operation in 1980, the two others in 1991, and the last one is under commissioning. The development of the LHE cryoplant was concerned with the construction of the new superconducting accelerator Nuclotron aimed to accelerate nuclei and heavy ions up to energies of 6 GeV/u. The first test run at the Nuclotron was carried out in March 1993, and the total running time has been about 2000 hours up to now. Since 1992 the cryoplant has been intensively used by the users outside the Laboratory. More than a million liters of liquid helium was provided in 1993 for such users. The reliability of the cryoplant system was as high as 98 percent for 4500 hours of operation in 1993-1994. 7 refs., 4 figs., 1 tab

  18. Self-trapping of helium in metals

    International Nuclear Information System (INIS)

    Wilson, W.D.; Bisson, C.L.; Baskes, M.I.

    1981-01-01

    Atomistic calculations are presented which demonstrate that helium atoms in a metal lattice are able to cluster with each other, producing vacancies and nearby self-interstitial defects. Even a small number of helium atoms is found to be sufficient to create these large distortions. As few as five interstitial helium can spontaneously produce a lattice vacancy and nearby self-interstitial. An eight-helium-atom cluster gives rise to two such defects, and 16 helium atoms to more than five self-interstitial vacancy pairs. It was noted that the self-interstitials prefer to agglomerate on the same ''side'' of the helium cluster rather than to spread themselves out uniformly. The binding energy of each additional helium atom to these clusters increases with helium concentration and the trap is apparently unsaturable. A rate theory using these atomistic binding energies has been used to calculate the kinetics of helium-bubble nucleation and growth. The results are consistent with measurements of the properties of helium resulting from tritium decay

  19. Helium in inert matrix dispersion fuels

    International Nuclear Information System (INIS)

    Veen, A. van; Konings, R.J.M.; Fedorov, A.V.

    2003-01-01

    The behaviour of helium, an important decay product in the transmutation chains of actinides, in dispersion-type inert matrix fuels is discussed. A phenomenological description of its accumulation and release in CERCER and CERMET fuel is given. A summary of recent He-implantation studies with inert matrix metal oxides (ZrO 2 , MgAl 2 O 4 , MgO and Al 2 O 3 ) is presented. A general picture is that for high helium concentrations helium and vacancy defects form helium clusters which convert into over-pressurized bubbles. At elevated temperature helium is released from the bubbles. On some occasions thermal stable nano-cavities or nano-pores remain. On the basis of these results the consequences for helium induced swelling and helium storage in oxide matrices kept at 800-1000 deg. C will be discussed. In addition, results of He-implantation studies for metal matrices (W, Mo, Nb and V alloys) will be presented. Introduction of helium in metals at elevated temperatures leads to clustering of helium to bubbles. When operational temperatures are higher than 0.5 melting temperature, swelling and helium embrittlement might occur

  20. Modelling and control of a cryogenic refrigerator: Application to the 800 W at 4.5 K cryogenic station of the CEA Grenoble

    International Nuclear Information System (INIS)

    Clavel, Fanny

    2011-01-01

    This thesis is concerned with the development of a novel control scheme on a helium refrigerator subject to high pulsed loads. Such disturbance will happen during the cooling of the superconductive magnet, used in tokamak configuration. A dynamical model of a cryogenic station, which offers a cooling capacity of 800 W at 4.5 K, has been produced. The modelling is based on the theoretical equations of thermodynamics, thermal physics and hydraulics and takes into account the non linear properties of helium at low temperature. Based on this model, a new control strategy has been developed for each of the two parts of the refrigerator: the warm compression system and the cold box. Experimental results show significant improvement with multivariable controllers as compared with the PIDs in the presence of high pulsed loads. An observer of the thermal load of the helium bath has also been developed. The model is constructed by identification using internal measures of the refrigerator. It can be used as condition monitoring tool for operators. (author)

  1. Scanning Quantum Cryogenic Atom Microscope

    Science.gov (United States)

    Yang, Fan; Kollár, Alicia J.; Taylor, Stephen F.; Turner, Richard W.; Lev, Benjamin L.

    2017-03-01

    Microscopic imaging of local magnetic fields provides a window into the organizing principles of complex and technologically relevant condensed-matter materials. However, a wide variety of intriguing strongly correlated and topologically nontrivial materials exhibit poorly understood phenomena outside the detection capability of state-of-the-art high-sensitivity high-resolution scanning probe magnetometers. We introduce a quantum-noise-limited scanning probe magnetometer that can operate from room-to-cryogenic temperatures with unprecedented dc-field sensitivity and micron-scale resolution. The Scanning Quantum Cryogenic Atom Microscope (SQCRAMscope) employs a magnetically levitated atomic Bose-Einstein condensate (BEC), thereby providing immunity to conductive and blackbody radiative heating. The SQCRAMscope has a field sensitivity of 1.4 nT per resolution-limited point (approximately 2 μ m ) or 6 nT /√{Hz } per point at its duty cycle. Compared to point-by-point sensors, the long length of the BEC provides a naturally parallel measurement, allowing one to measure nearly 100 points with an effective field sensitivity of 600 pT /√{Hz } for each point during the same time as a point-by-point scanner measures these points sequentially. Moreover, it has a noise floor of 300 pT and provides nearly 2 orders of magnitude improvement in magnetic flux sensitivity (down to 10-6 Φ0/√{Hz } ) over previous atomic probe magnetometers capable of scanning near samples. These capabilities are carefully benchmarked by imaging magnetic fields arising from microfabricated wire patterns in a system where samples may be scanned, cryogenically cooled, and easily exchanged. We anticipate the SQCRAMscope will provide charge-transport images at temperatures from room temperature to 4 K in unconventional superconductors and topologically nontrivial materials.

  2. A Cryogenic Infrared Calibration Target

    Science.gov (United States)

    Wollack, E. J.; Kinzer, R. E., Jr.; Rinehart, S. A.

    2014-01-01

    A compact cryogenic calibration target is presented that has a peak diffuse reflectance, R target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to approx.4 K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials-Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder-are characterized and presented

  3. Cryogenic fluid management program flight concept definition

    Science.gov (United States)

    Kroeger, Erich

    1987-01-01

    The Lewis Research Center's cryogenic fluid management program flight concept definition is presented in viewgraph form. Diagrams are given of the cryogenic fluid management subpallet and its configuration with the Delta launch vehicle. Information is given in outline form on feasibility studies, requirements definition, and flight experiments design.

  4. Helium diffusion in nickel at high temperatures

    International Nuclear Information System (INIS)

    Philipps, V.

    1980-09-01

    Helium has been implanted at certain temperatures between 800 and 1250 0 C into single and polycrystalline Ni-samples with implantation depths between 15 and 90 μm. Simultaneously the helium reemission from the sample is measured by a mass-spectrometer. It has been shown that the time dependence of the observed reemission rate is governed by volume diffusion of the helium. Measuring this time dependence as a function of temperature the helium diffusion constant has been determined. The He-diffusion is interpreted as a interstitial diffusion hindered by thermal vacancies. Depending on the implantation depth more or less of the implanted helium remains in the sample and forms large helium bubbles. (orig./GSCH)

  5. Backscattered Helium Spectroscopy in the Helium Ion Microscope: Principles, Resolution and Applications

    NARCIS (Netherlands)

    van Gastel, Raoul; Hlawacek, G.; Dutta, S.; Poelsema, Bene

    2015-01-01

    We demonstrate the possibilities and limitations for microstructure characterization using backscattered particles from a sharply focused helium ion beam. The interaction of helium ions with matter enables the imaging, spectroscopic characterization, as well as the nanometer scale modification of

  6. Helium leak testing methods in nuclear applications

    International Nuclear Information System (INIS)

    Ahmad, Anis

    2004-01-01

    Helium mass-spectrometer leak test is the most sensitive leak test method. It gives very reliable and sensitive test results. In last few years application of helium leak testing has gained more importance due to increased public awareness of safety and environment pollution caused by number of growing chemical and other such industries. Helium leak testing is carried out and specified in most of the critical area applications like nuclear, space, chemical and petrochemical industries

  7. Applicability of ASST-A helium refrigeration system for JLab End Station Refrigerator

    Science.gov (United States)

    Hasan, N.; Knudsen, P.; Ganni, V.

    2017-12-01

    The MØLLER experiment at Jefferson Lab (JLab) is a high power (5 kW) liquid hydrogen target scheduled to be operational in the 12 GeV-era. At present, cryogenic loads and targets at three of JLab’s four experimental halls are supported by the End Station Refrigerator (ESR) - a CTI/Helix 1.5 kW 4.5 K refrigerator. It is not capable of supporting the high power target load and a capacity upgrade of the ESR cryogenic system is essential. The ASST-A helium refrigeration system is a 4 kW 4.5 K refrigerator. It was designed and used for the Superconducting Super Collider Lab (SSCL) magnet string test and later obtained by JLab after the cancellation of that project. The modified ASST-A refrigeration system, which will be called ESR-II along with a support flow from JLab’s Central Helium Liquefier (CHL) is considered as an option for the End Station Refrigerator capacity upgrade. The applicability of this system for ESR-II under varying load conditions is investigated. The present paper outlines the findings of this process study.

  8. Progress on the MICE Liquid Absorber Cooling and Cryogenic Distribution System

    International Nuclear Information System (INIS)

    Green, M.A.; Baynham, E.; Bradshaw, T.; Drumm, P.; Ivanyushenkov, Y.; Ishimoto, S.; Cummings, M.A.C.; Lau, W.W.; Yang, S.Q.

    2005-01-01

    This report describes the progress made on the design of the cryogenic cooling system for the liquid absorber for the international Muon Ionization Cooling Experiment (MICE). The absorber consists of a 20.7-liter vessel that contains liquid hydrogen (1.48 kg at 20.3 K) or liquid helium (2.59 kg at 4.2 K). The liquid cryogen vessel is located within the warm bore of the focusing magnet for the MICE. The purpose of the magnet is to provide a low beam beta region within the absorber. For safety reasons, the vacuum vessel for the hydrogen absorber is separated from the vacuum vessel for the superconducting magnet and the vacuum that surrounds the RF cavities or the detector. The absorber thin windows separate the liquid in the absorber from the absorber vacuum. The absorber vacuum vessel also has thin windows that separate the absorber vacuum space from adjacent vacuum spaces. Because the muon beam in MICE is of low intensity, there is no beam heating in the absorber. The absorber can use a single 4 K cooler to cool either liquid helium or liquid hydrogen within the absorber

  9. Behaviour of helium after implantation in molybdenum

    International Nuclear Information System (INIS)

    Viaud, C.; Maillard, S.; Carlot, G.; Valot, C.; Gilabert, E.; Sauvage, T.; Peaucelle, C.; Moncoffre, N.

    2009-01-01

    This study deals with the behaviour of helium in a molybdenum liner dedicated to the retention of fission products. More precisely this work contributes to evaluate the release of implanted helium when the gas has precipitated into nanometric bubbles close to the free surface. A simple model dedicated to calculate the helium release in such a condition is presented. The specificity of this model lays on the assumption that the gas is in equilibrium with a simple distribution of growing bubbles. This effort is encouraging since the calculated helium release fits an experimental dataset with a set of parameters in good agreement with the literature

  10. Helium turbo-expander with an alternator

    International Nuclear Information System (INIS)

    Akiyama, Yoshitane

    1980-01-01

    Study was made on a helium turbo-expander, the heart of helium refrigerator systems, in order to develop a system which satisfies the required conditions. A helium turbo-expander with externally pressurized helium gas bearings at the temperature of liquid nitrogen and an alternator as a brake have been employed. The essential difference between a helium turbo-expander and a nitrogen turbo-expander was clarified. The gas bearing lubricated with nitrogen at room temperature and the gas bearing lubricated with helium at low temperature were tested. The flow rate of helium in a helium refrigerator for a large superconducting magnet is comparatively small, therefore a helium turbine must be small, but the standard for large turbine design can be applied to such small turbine. Using the alternator as a brake, the turbo-expander was easily controllable electrically. The prototype turbo-expander was made, and the liquefaction test with it and MHD power generation test were carried out. (Kako, I.)

  11. Helium supply demand in future years

    International Nuclear Information System (INIS)

    Laverick, C.

    1975-01-01

    Adequate helium will be available to the year 2000 AD to meet anticipated helium demands for present day applications and the development of new superconducting technologies of potential importance to the nation. It is almost certain that there will not be enough helium at acceptable financial and energy cost after the turn of the century to meet the needs of the many promising helium based technologies now under development. Serious consideration should be given to establishing priorities in development and application based upon their relative value to the country. In the first half of the next century, three ways of estimating helium demand lead to cumulative ranges of from 75 to 125 Gcf (economic study), 89 to 470 Gcf (projected national energy growth rates) and 154 to 328 Gcf (needs for new technologies). These needs contrast with estimated helium resources in natural gas after 2000 AD which may be as low as 10 or 126 Gcf depending upon how the federal helium program is managed and the nation's natural gas resources are utilized. The technological and financial return on a modest national investment in further helium storage and a rational long term helium program promises to be considerable

  12. Cryogenic infrastructure at BESSY II. Inventory and outlook; Kryogene Infrastruktur bei BESSY II. Bestand und Ausblick

    Energy Technology Data Exchange (ETDEWEB)

    Heling, Svenja; Anders, Wolfgang; Heinrich, Jochen; Hellwig, Axel; Janke, Karsten; Molder, Benjamin; Rotterdam, Stefan [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany)

    2017-07-01

    The Helmholtz Centre Berlin operates the BESSY II electron storage ring at the Adlershof site. A helium condenser is installed to supply the superconducting wavelength shifter installed in the storage ring with liquid helium. Another liquefier, including a comprehensive cryogenic infrastructure, supplies helium at 1.8 K to several test stands, especially for superconducting cavity resonators. In addition to the operation of the existing plants, a new type of accelerator is currently being set up as part of the bERLinPro project. In order to ensure the required supply of liquid helium, one of the existing helium condensers will be relocated and the plant will be extended by a 10,000 l dewar, three valve boxes, a cold compressor box, a warm pumping station and an 80 K helium system. In addition, the future project BESSY VSR, a further development of the BESSY II storage ring, will see the procurement of a third refrigeration system. A challenge here will be the year-round continuous operation. This paper explains the structure of the plants described above in more detail and provides an insight into the challenges of plant design. Finally, the planned future expansions will be outlined. [German] Das Helmholtz-Zentrum Berlin betreibt am Standort Adlershof u.a. den Elektronenspeicherring BESSY II. Fuer die Versorgung der im Speicherring installierten supraleitenden Wellenlaengenschieber mit Fluessighelium ist ein Heliumverfluessiger installiert. Ein weiterer Verfluessiger, inklusive umfassender kryogener Infrastruktur, versorgt mehrere Teststaende, vor allem fuer supraleitende Hohlraumresonatoren, mit Helium bei 1,8 K. Neben dem Betrieb der existierenden Anlagen wird derzeit ein neuartiger Beschleunigertyp im Rahmen des Pro-jektes bERLinPro aufgebaut. Um die benoetigte Versorgung mit Fluessighelium zu gewaehrleisten, wird einer der bestehenden Heliumverfluessiger umgezogen sowie die Anlage um u.a. einen 10.000 l Dewar, drei Ventilboxen, eine Kaltkompressorbox, einen

  13. Cryogen-free dilution refrigerators

    International Nuclear Information System (INIS)

    Uhlig, K

    2012-01-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4 He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4 He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  14. Cryogen-free dilution refrigerators

    Science.gov (United States)

    Uhlig, K.

    2012-12-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  15. Cryogenics for HL-LHC

    Science.gov (United States)

    Tavian, L.; Brodzinski, K.; Claudet, S.; Ferlin, G.; Wagner, U.; van Weelderen, R.

    The discovery of a Higgs boson at CERN in 2012 is the start of a major program of work to measure this particle's properties with the highest possible precision for testing the validity of the Standard Model and to search for further new physics at the energy frontier. The LHC is in a unique position to pursue this program. Europe's top priority is the exploitation of the full potential of the LHC, including the high-luminosity upgrade of the machine and detectors with an objective to collect ten times more data than in the initial design, by around 2030. To reach this objective, the LHC cryogenic system must be upgraded to withstand higher beam current and higher luminosity at top energy while keeping the same operation availability by improving the collimation system and the protection of electronics sensitive to radiation. This chapter will present the conceptual design of the cryogenic system upgrade with recent updates in performance requirements, the corresponding layout and architecture of the system as well as the main technical challenges which have to be met in the coming years.

  16. New helium spectrum variable and a new helium-rich star

    International Nuclear Information System (INIS)

    Walborn, N.R.

    1974-01-01

    HD 184927, known previously as a helium-rich star, has been found to have a variable helium spectrum; the equivalent widths of five He I lines are larger by an average of 46 percent on a 1974 spectrogram than on one obtained with the same equipment in 1970. HD 186205 has been found to be a new, pronounced helium-rich star. (auth)

  17. Helium transfer line installation details.

    CERN Multimedia

    G. Perinic

    2007-01-01

    A particularity of the 32 m long four in one helium transfer line in between the cold box in USC55 and the cavern UX5 is the fact that the transfer line passes through a hole in the crane rail support beam. In order to ensure the alignment of the suspension rail in the interconnecting tunnel with the hole in the rail support as well as the connection points at both ends required precise measurements of the given geometries as well as the installation of a temporary target for the verification of the theoretical predictions.

  18. Helium bubble bursting in tungsten

    International Nuclear Information System (INIS)

    Sefta, Faiza; Juslin, Niklas; Wirth, Brian D.

    2013-01-01

    Molecular dynamics simulations have been used to systematically study the pressure evolution and bursting behavior of sub-surface helium bubbles and the resulting tungsten surface morphology. This study specifically investigates how bubble shape and size, temperature, tungsten surface orientation, and ligament thickness above the bubble influence bubble stability and surface evolution. The tungsten surface is roughened by a combination of adatom “islands,” craters, and pinholes. The present study provides insight into the mechanisms and conditions leading to various tungsten topology changes, which we believe are the initial stages of surface evolution leading to the formation of nanoscale fuzz

  19. Large volume cryogenic silicon detectors

    International Nuclear Information System (INIS)

    Braggio, C.; Boscardin, M.; Bressi, G.; Carugno, G.; Corti, D.; Galeazzi, G.; Zorzi, N.

    2009-01-01

    We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm 3 , cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

  20. Large volume cryogenic silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Braggio, C. [Dipartimento di Fisica, Universita di Padova, via Marzolo 8, 35131 Padova (Italy); Boscardin, M. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy); Bressi, G. [INFN sez. di Pavia, via Bassi 6, 27100 Pavia (Italy); Carugno, G.; Corti, D. [INFN sez. di Padova, via Marzolo 8, 35131 Padova (Italy); Galeazzi, G. [INFN lab. naz. Legnaro, viale dell' Universita 2, 35020 Legnaro (Italy); Zorzi, N. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy)

    2009-12-15

    We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm{sup 3}, cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.