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superconducting-magnet

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MOYCGM01 FAIR: Challenges Overcome and Still to be Met antiproton, dipole, ion, vacuum 17
 
  • H. Stöcker
    GSI, Darmstadt
  FAIR will be one of the leading accelerator facilities worldwide making use of a highly sophisticated and cost-effective accelerator concept. The intensity frontier will be pushed by several orders of magnitude for the primary and especially for the secondary beams. To reach the unprecedented beam parameters several technical challenges such as operation with high brightness, high current beams, control of the dynamic vacuum pressure or the design of rapidly cycling superconducting magnets have to be mastered. For most of those challenges solutions have been found and prototypes are being built. The remaining open questions are addressed in close collaborations with the partners of FAIR.  
slides icon Slides  
 
MOPP099 MICE RF System power-supply, controls, emittance, factory 787
 
  • A. J. Moss, P. A. Corlett, J. F. Orrett, J. H.P. Rogers
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  The Muon Ionisation Cooling Experiment (MICE) at the Rutherford Appleton Laboratory uses normal conducting copper cavities to re-accelerate a muon beam after it has been retarded by liquid hydrogen absorbers. Each cavity operates at 200MHz and requires 1MW of RF power in a 1ms pulse at a repetition rate of 1Hz. In order to provide this power, a Thales TH116 triode, driven by a Burle 4616 tetrode is used, with each amplifier chain providing ~2.5MW. This power is then split between 2 cavities. The complete MICE RF system is described, including details of the low level RF, the power amplifiers and the coaxial power distribution system.  
 
TUPC134 Results from Commissioning of the Energy Extraction Facilities of the LHC Machine extraction, dipole, quadrupole, simulation 1383
 
  • K. H. Mess, G.-J. Coelingh, K. Dahlerup-Petersen
    CERN, Geneva
  The risk of damage to the superconducting magnets, busbars and current leads of the LHC machine in case of a resistive transition (quench) is being minimized by adequate protection. The protection is based on early quench detection, bypassing the quenching magnets by cold diodes, energy density dilution in the quenching magnets using heaters and, eventually, energy extraction. For two hundred and twenty-six LHC circuits (600 A and 13 kA) extraction of the stored magnetic energy to external dump resistors was required. All these systems are now installed in the machine and the final hardware commissioning has been undertaken. After a short description of the topology and definitive features, layouts and parameters of these systems the paper will focus on the results from their successful commissioning and an analysis of the system performance.  
 
TUPD035 Modeling of the RF-shield Sliding Contact Fingers for the LHC Cryogenic Beam Vacuum Interconnects Using Implicit and Explicit Finite Element Formulations vacuum, simulation, alignment, shielding 1503
 
  • D. Ramos
    CERN, Geneva
  The short interconnect length between the LHC superconducting magnets required the development of an optimised RF shielded bellows module, with a low impedance combined with compensation for large thermal displacements and alignment lateral offsets. Each bellows is shielded by slender copper-beryllium fingers working as pre-loaded beams in order to provide a constant force at the sliding contact. Unless the sliding friction and some geometrical parameters of the fingers are kept within a limited range, a large irreversible lateral deflection towards the vacuum chamber axis may occur and eventually block the beam aperture. The finite element analysis presented here simulates this failure mechanism providing a complete understanding of the finger behavior as well as the influence of the various design parameters. An implicit non-linear two-dimensional model integrating friction on the sliding contacts, geometrical non-linearity and plasticity was implemented in a first stage. The design was then verified through the whole working range using an explicit formulation, which overcame the instabilities resulting from the sudden release of internal energy stored in the finger.  
 
TUPP110 Rotative Systems for Dose Distribution in Hadrontherapy (Gantries) dipole, ion, cryogenics, proton 1779
 
  • M. J. Bajard
    UCBL, Villeurbanne
  • F. A. Kircher
    CEA, Grenoble
  Tumour treatments with high velocity ion beams or protons are characterised by a great depth precision (Bragg pic) and a low divergence for dose delivery in very small volumes. In order to spare normal tissues before and around the tumour it is necessary to have the choice of the beam incidence because the patient cannot be moved. Different devices have been built mainly exocentric and isocentric. Many others are being studied. Cryogenic solutions are analysed to reduce the total mass in rotation. For example it would be very interesting to choose a superconductive solution for the last 90° dipole.  
 
WEPD005 Scaling Laws for Magnetic Energy in Superconducting Quadrupoles quadrupole, collider, luminosity, positron 2407
 
  • F. Borgnolutti, E. Todesco
    CERN, Geneva
  • A. Mailfert
    ENSEM, Vandoeuvre lès Nancy
  The stored energy in superconducting magnets is one of the main ingredients needed for the quench calculation and for desingin quench protections. Here we proposed an analytical formula based on the Fourier transformation of the current density flowing within the winding to determine the magnetic energy stored in superconducting quadrupoles made of sector coils. Two corrective coefficients allowing to estimate the energy enhancement produced either by current grading or by the presence of an unsaturated iron yoke are respectively derived from a numerical and an analytical study. This approach is applied to a set of real quadrupoles to test the validity limits of the scaling law, which are shown to be of 5-10%.  
 
WEPD013 Four-Coil Superconducting Helical Solenoid Model for Muon Beam Cooling beam-cooling, controls, quadrupole, dipole 2431
 
  • V. S. Kashikhin, N. Andreev, A. N. Didenko, V. Kashikhin, M. J. Lamm, A. V. Makarov, K. Yonehara, A. V. Zlobin
    Fermilab, Batavia, Illinois
  • R. P. Johnson, S. A. Kahn
    Muons, Inc, Batavia
  Novel configurations of superconducting magnets for helical muon beam cooling channels and demonstration experiments are being designed at Fermilab. The magnet system for helical cooling channels has to generate longitudinal solenoidal and transverse helical dipole and helical quadrupole fields. This paper discusses the Helical Solenoid model design and manufacturing of a 0.6 m diameter, 4-coil solenoid prototype to prove the design concept, fabrication technology, and the magnet system performance. Results of magnetic and mechanical designs with the 3D analysis by TOSCA, ANSYS and COMSOL will be presented. The model quench performance and the test setup in the FNAL Vertical Magnet Test Facility cryostat will be discussed.  
 
WEPD020 Stability of Superconducting Wire in Magnetic Field cryogenics, power-supply, dipole 2449
 
  • K. Ruwali
    GUAS/AS, Ibaraki
  • K. Hosoyama, K. Nakanishi
    KEK, Ibaraki
  • Y. Teramoto, A. Yamanaka
    Toyobo Research Institute, Shiga
  Main cause of premature quench in superconducting magnet is the heat generated due to superconducting wire motion. The wire motion occurs where electromagnetic force to conductors exceeds frictional force on surfaces of the conductors. Hence, frictional properties of the conductors and winding structures are important parameters for characterizing stability of the superconducting windings. An experimental setup was prepared to detect wire movement by observing spike in voltage of the superconducting sample wire. A detailed study was carried out in order to study superconducting wire motion under different experimental conditions such as varying applied load to specimen wire, back up field, varying the interface of superconductor and base material. The base materials used are polyimide film and Dyneema. The Dyneema has low frictional coefficient and negative thermal expansion. In the case of Dyneema, it is found that amplitude of voltage generated due to wire motion reduces and also relatively smooth motion of wire is observed. These effects are attributed to the low frictional coefficient. The experimental observation will be discussed in detail.  
 
WEPD022 High Field Superconductor for Muon Cooling collider, beam-cooling, emittance, magnet-design 2455
 
  • J. Schwartz
    NHMFL, Tallahassee, Florida
  • R. P. Johnson, S. A. Kahn, M. Kuchnir
    Muons, Inc, Batavia
  High temperature superconductors (HTS) have been shown to carry significant current density in the presence of extremely high magnetic fields when operated at low temperature. The successful design of magnets needed for high energy physics applications using such high field superconductor (HFS) depends critically on the detailed wire or tape parameters which are still under development and not yet well-defined. In the project reported here, we are developing HFS for accelerator use by concentrating on the design of an innovative magnet that will have a useful role in muon beam cooling. Measurements of available materials and a conceptual design of a high field solenoid using YBCO HFS conductor are being analyzed with the goal of providing useful guidance to superconductor manufacturers for materials well suited to accelerator applications.  
 
WEPD023 Multi-purpose Fiber Optic Sensors for HTS Magnets monitoring, optics, controls, background 2458
 
  • J. Schwartz
    NHMFL, Tallahassee, Florida
  • R. P. Johnson, S. A. Kahn, M. Kuchnir
    Muons, Inc, Batavia
  Magnets using new high temperature superconductor (HTS) materials are showing great promise for high magnetic field and/or radiation environment applications such as particle accelerators, NMR, and the plasma-confinement systems for fusion reactors. The development and operation of these magnets is limited, however, because appropriate sensors and diagnostic systems are not yet available to monitor the manufacturing and operational processes that dictate success. Optical fibers are being developed to be imbedded within the HTS magnets to monitor strain, temperature and irradiation, and to detect quenches. In the case of Bi2212, the fiber will be used as a heat treatment process monitor to ensure that the entire magnet has reached thermal equilibrium. Real-time measurements will aid the development of high-field magnets that are subject to large Lorentz forces and allow the effective detection of quenches so that the stored energy of operating magnets can be extracted and/or dissipated without damaging the magnet.  
 
WEPD026 The Special LHC Interconnections: Technologies, Organization and Quality Control cryogenics, insertion, controls, vacuum 2464
 
  • J.-P. G. Tock, F. F. Bertinelli, D. Bozzini, P. Cruikshank, O. Desebe, M. F. Felip-Hernando, C. Garion, A. Jacquemod, N. Kos, F. Laurent, A. Poncet, S. Russenschuck, I. Slits, L. R. Williams
    CERN, Geneva
  • L. Hajduk
    HNINP, Krakow
  • L. Vaudaux
    IEG, St-Genis-Pouilly
  In addition to the standard interconnections of the continuous cryostat of the Large Hadron Collider (LHC), there exists a variety of special ones related to specific components and assemblies, such as cryomagnets of the insertion regions, electrical feedboxes and superconducting links. Though they are less numerous, their specificities created many additional interconnection types, requiring a larger variety of assembly operations and quality control techniques, keeping very high standards of quality. Considerable flexibility and adaptability from all the teams involved (CERN staff, collaborating institutes, contractors) were the key points to ensure the success of this task. This paper first describes the special interconnections and presents the employed technologies which are adapted from the standard work. Then, the organization adopted for this non-repetitive work is described. Examples of non-conformities that were resolved are also discussed. Figures of merit in terms of quality and productivity are given and compared with standard interconnections work.  
 
WEPD027 A new cable insulation scheme improving heat transfer in Nb-Ti superconducting accelerator magnets dipole, quadrupole, interaction-region, collider 2467
 
  • D. Tommasini, D. Richter
    CERN, Geneva
  The next applications of superconducting magnets for interaction regions of particle colliders or for fast cycled accelerators require dealing with large heat fluxes generated or deposited in the coils. Last year* we have anticipated the theoretical potential for a large improvement of heat transfer of state of the art Nb-Ti cable insulations in superfluid helium, such as the one used for the LHC superconducting magnets. In this paper we present and discuss new experimental results, confirming that a factor of 5 increase of the allowed heat flux from coil to coolant can be obtained with the new insulation topology while keeping a sound margin in the dielectric performance.

*M. La China, D. Tommasini. “Cable Insulation Scheme to Improve Heat Transfer to Superfluid Helium in Nb-Ti Accelerator Magnets,” MT-20, Philadelphia, USA, August 2007.

 
 
WEPD041 Continuous Operation of Cryogenic System for Synchrotron Light Source cryogenics, controls, storage-ring, synchrotron 2503
 
  • F. Z. Hsiao, S.-H. Chang, W.-S. Chiou, H. C. Li, H. H. Tsai
    NSRRC, Hsinchu
  The availability of user time is an important index for the performance evaluation of a synchrotron light source. In NSRRC two cryogenic plants are installed for liquid helium supply to the superconducting magnets and the superconducting cavity of the electron storage ring. As a subsystem of the storage ring, the objective of continuous helium supply without interruption is important for the cryogenic plant. The target to shorten the recovery time of the storage ring, if the cryogenic plant trips, is another issue. Component failure and system maintenance are two main reasons interrupting operation of the cryogenic plant. This paper shows our strategy on the scheduled maintenance of either the cryogenic plant or the utility system to keep continuous liquid helium supply. Two tests to shorten the recovery time are presented: the first is liquid helium supply from both cryogenic plants simultaneously; the second is restarting the on-duty cryogenic plant with the other dewar providing helium to the superconducting devices.  
 
WEPD042 Development of a Simulation Module for the Cryogenic System cryogenics, simulation, controls, synchrotron 2506
 
  • H. C. Li, S.-H. Chang, W.-S. Chiou, F. Z. Hsiao, H. H. Tsai
    NSRRC, Hsinchu
  In NSRRC two 450W cryogenic systems were installed on the year 2002 and 2006, respectively. After long time operation some behavior and setting parameters of the cryogenic system did not satisfy our requirement because of the deterioration of electrical sensors and valves. To ask the manufacturer to solve those problems, it took lots of time in the communication of problem description and the modification of control program. A simulation module for the cryogenic system is thus developed to trace the procedure before and after modification of the control program. This paper details the simulation module and shows the usefulness of this module on evaluation of the software modification for cryogenic system.  
 
WEPD044 Efficiency Analysis for the Cryogenic System at NSRRC cryogenics, simulation, controls, synchrotron 2512
 
  • H. H. Tsai, S.-H. Chang, W.-S. Chiou, F. Z. Hsiao, H. C. Li
    NSRRC, Hsinchu
  Three superconducting magnets and one superconducting cavity for RF are cooled by two 450W liquid helium system at NSRRC. These two systems were made up of Claude cycle which is usually compared in their performance to that of the ideal Carnot cycle. This paper presents the efficiency analysis for the cryogenic system. Based on the analysis, the power transfer to the process change for the operation will be performed. In addition, it also shows the way to identify the problems when done the trouble shooting for part of erratic response of the plant. The carnot efficiency also provides an important index of the performance, especially when we done the process control.  
 
WEPP010 Scheduling the Powering Tests cryogenics, extraction, instrumentation, simulation 2545
 
  • K. Foraz, E. Barbero-Soto, B. Bellesia, M. P. Casas Lino, C. Fernandez-Robles, M. Pojer, R. I. Saban, R. Schmidt, M. Solfaroli Camillocci, A. Vergara-Fernández
    CERN, Geneva
  The Large Hadron Collider is now entering in its final phase before receiving beam, and the activities at CERN between 2007 and 2008 have shifted from installation work to the commissioning of the technical systems (“hardware commissioning”). Due to the unprecedented complexity of this machine, all the systems are or will be tested as far as possible before the cool-down starts. Systems are firstly tested individually before being globally tested together. The architecture of LHC, which is partitioned into eight cryogenically and electrically independent sectors, allows the commissioning on a sector by sector basis. When a sector reaches nominal cryogenic conditions, commissioning of the magnet powering system to nominal current for all magnets can be performed. This paper briefly describes the different activities to be performed during the powering tests of the superconducting magnet system and presents the scheduling issues raised by co-activities as well as the management of resources.  
 
WEPP031 Energy Deposited in the High Luminosity Inner Triplets of the LHC by Collision Debris luminosity, quadrupole, insertion, kaon 2587
 
  • E. Y. Wildner, F. Cerutti, A. Ferrari, C. Hoa, J.-P. Koutchouk
    CERN, Geneva
  • F. Broggi
    INFN/LASA, Segrate (MI)
  • N. V. Mokhov
    Fermilab, Batavia, Illinois
  The 14 TeV center of mass proton-proton collisions in the LHC produce not only interesting events for physics but also debris ending up in the accelerator equipment, in particular in the superconducting magnet coils. Evaluations of the deposited heat, that has to be transferred to the cryogenic system, have been made to guarantee that the energy deposition in the superconducting magnets does not exceed limits for magnet quenching and the capacity of the cryogenic system. The models of the LHC baseline are detailed and include description of, for energy deposition, essential elements like beam-pipes and corrector magnets. The evaluations made using the Monte-Carlo code FLUKA are compared to previous studies using MARS. For the comparison and consolidation of the calculations, a dedicated study of a simplified model has been made, showing satisfactory agreement.  
 
WEPP069 Tracking Tools to Estimate the Quench Time Constants for Magnet Failures in LHC simulation, insertion, beam-losses, proton 2677
 
  • A. Gomez Alonso
    CERN, Geneva
  At LHC, beam losses, with about 360MJ of stored energy per beam at nominal collision operation, are potentially dangerous for the accelerator equipment and can also affect the operational efficiency by inducing quenches in superconducting magnets. Magnet failures may affect the beam leading to proton losses primarily in collimators and secondary in superconducting magnets due to scattering of protons from collimator jaws. The evolution of the beam during magnet failures has been simulated using MAD-X with a variable magnetic field. The impacts of particles in the collimators have been recorded as a function of time. A second program, CollTrack, has been used to determine the loss patterns of scattered particles from each collimator as a function of the initial impact parameter. The magnets that are likely to quench are identified and an estimation of the time between the beginning of a failure and a quench is obtained by combining the results from the simulations. The time to a start of a quench is a relevant parameter to determine the dump threshold of beam loss monitors in order to optimize protection redundancy and operation smoothness for LHC.  
 
THPC150 The Use of Software in Safety Critical Interlock Systems of the LHC monitoring, proton, diagnostics 3342
 
  • A. Castaneda, F. B. Bernard, P. Dahlen, I. Romera, B. Todd, D. Willeman, M. Zerlauth
    CERN, Geneva
  This paper will provide an overview of the software development and management techniques applied to interlock systems in the CERN accelerator complex. Despite the in essence hardware based approach, software and configuration data is present in various forms and has to be treated with special care when aiming at safe, reliable and available protection systems. Several techniques and methods deployed in the LHC machine protection systems are highlighted, regarding data management and version tracking, hardware choices, commissioning procedures, testing methods and first operational experiences with the systems in CERN's accelerator complex.  
 
THPC151 The Post-Mortem Analysis Software Used for the Electrical Circuit Commissioning of the LHC extraction, controls, quadrupole, instrumentation 3345
 
  • H. Reymond, O. O. Andreassen, C. Charrondiere, D. Kudryavtsev, P. R. Malacarne, E. Michel, A. Raimondo, A. Rijllart, R. Schmidt, N. Trofimov
    CERN, Geneva
  The hardware commissioning of the LHC has started in the first quarter of 2007, with the sector 7-8. A suite of software tools has been developed to help the experts with the access, visualization and analysis of the result of the tests. Using the experience obtained during this phase and the needs to improve the parallelism and the automation of the electrical circuits commissioning, a new user interface has been defined to have an overview of all pending tests and centralise the access to the different analysis tools. This new structure has been intensely used on sector 4-5 and during this time the test procedures for different types of electrical circuits have been verified, which has also allowed the implementation of new rules and features in the associated software. The hardware commissioning of the electrical circuits enters in a more critical phase in 2008, were the number of the tests executed increases rapidly as test will be performed in parallel on different sectors. This paper presents an overview on the post mortem analysis software, from its beginning as a simple graphical interface to the actual suite of integrated analysis tools.  
 
THPP132 Review of the Initial Phases of the LHC Power Converter Commissioning controls, quadrupole, instrumentation, cryogenics 3670
 
  • H. Thiesen, D. Nisbet
    CERN, Geneva
  The LHC requires more than 1700 power converter systems that supply between 60A and 12kA of precisely regulated current to the superconducting magnets. For the first time at CERN these converters have been installed underground in close proximity to many other accelerator systems. In addition to the power converters themselves, many utilities such as air and water cooling, electrical power, communication networks and magnet safety systems needed to be installed and commissioned as a single system. Due to the complexity of installing and commissioning such a large infrastructure, with inevitable interaction between the different systems, a three phase test strategy was developed. The first phase comprised the manufacture, integration and reception tests of all converter sub-systems necessary for powering. The second phase covered the commissioning of all the power converters installed in their final environment with the utilities. The third phase will add the superconducting magnets and will not be covered by this paper. The planning and execution that have led to the successful completion of these initial phases are described. Results and conclusions of the testing are presented.