EPAC08 - Classification:07 Accelerator Technology Main Systems/T10 Superconducting Magnets

07 Accelerator Technology Main Systems

T10 Superconducting Magnets

Paper	Title	Page
WEOBM01	R&D Activities Aimed at Developing a Curved Fast Ramped Superconducting Dipole for FAIR SIS300	1950
	P. Fabbricatore, S. Farinon, R. Musenich INFN Genova, Genova F. Alessandria, G. Bellomo, G. Volpini INFN/LASA, Segrate (MI) U. Gambardella INFN/LNF, Frascati (Roma) J. E. Kaugerts, G. Moritz GSI, Darmstadt R. Marabotto ASG, Genova M. Sorbi Universita' degli Studi di Milano & INFN, Segrate
	One of the basic components of the FAIR facility, under development at GSI, is the synchrotron SIS300 (300 Tm rigidity). In order to reach the required high intensities of proton and heavy ion beams, the magnets of this synchrotron have to be pulsed from the injection magnetic field of 1.5 T up to 4.5 T maximum field at the rate of 1 T/s. These 7.8 m long, cos-teta shaped coils with a 100 mm bore have the particular characteristic to be curved (the sagitta is 114 mm). All these aspects demand for a challenging R&D, aimed at the development of a low loss conductor and of a suitable winding technology for curved coil. Further design issues are related to the optimization of the stress distribution involving materials able to hold 10⁷ cycles and to the maximization of the heat transfer to coolant (supercritical helium at 4.7 K). At the present time, design activities are going on with the aim to design, construct and test a 3.8 m long prototype within 2009. In order to achieve this objective, several intermediate milestones are included in the R&D program. One of the most challenging is the industrial development of a method for winding a curved cos-teta dipole.
	Slides
WEPC114	Improved Winding of Superconducting Undulator and Measurement of Quenching Tolerance	2270
	J. C. Jan, C.-H. Chang, C.-S. Hwang, F.-Y. Lin NSRRC, Hsinchu
	The superconducting (SC) wire windings of the mini-pole superconducting undulator at National Synchrotron Radiation Research Center (NSRRC) have an improved performance. A precise measurement of the magnetic field was undertaken to examine the quality of the wire winding. We improved the insulation between wires and the iron pole to avoid SC wire degradation when the coil was trained up to high current. A Teflon coating (layer thickness 0.035-0.045 mm) on the iron pole is capable of providing insulation to 0.5 kV. We pasted extra Teflon tape (thickness 0.12 mm) on the coating layer; this Teflon tape serves as a buffer that avoids the SC wires scraping the Teflon coating layer during adjustment of the position of the SC wire during winding. A quenching experiment was also performed to detect the heat tolerance of the SC wires during extra heating of the beam duct; a heating tape (Ni80Cr20) simulated the heating of the beam duct by synchrotron radiation. The SC wires and heater are separated by the stainless steel (SS) beam duct (thickness 0.3 mm) and an epoxy layer (thickness 0.1 mm). This result is an important issue in cryostat design.
WEPD001	The Quality Control of the LHC Continuous Cryostat Interconnections	2398
	F. F. Bertinelli, D. Bozzini, P. Cruikshank, P. Fessia, W. Maan, A. Poncet, S. Russenschuck, F. Savary, Z. Sulek, J.-P. G. Tock, D. Tommasini, L. R. Williams CERN, Geneva P. B. Borowiec, A. Kotarba, S. Olek HNINP, Kraków A. Grimaud ALL43, Saint-Genis-Pouilly L. Vaudaux IEG, St-Genis-Pouilly
	The interconnections between the Large Hadron Collider (LHC) magnets have required some 40 000 TIG welded joints and 65 000 electrical splices. At the level of single joints and splices, non-destructive techniques find limited application: quality control is based on the qualification of the process and of operators, on the recording of production parameters, and on production samples. Visual inspection and process audits were the main techniques used. At the level of an extended chain of joints and splices - from a 53.5 m half-cell to a complete 2.7 km sector - quality control is based on vacuum leak tests, electrical tests and RF microwave reflectometry that progressively validated the work performed. Subsequent sector pressure tests, cryogenic circuits flushing with high pressure helium and cool-downs revealed a few unseen or new defects. The nature of defects is analyzed and classified according to their origin. Methods for defect localization are described. This paper presents an overview of the quality control techniques used and critically evaluates their effectiveness in progressively identifying defects, seeking lessons applicable to similar large, complex projects.
WEPD002	Magnetic Design Studies for the Final Focus Quadrupoles of the SuperB Large Crossing Angle Collision Scheme	2401
	E. Paoloni University of Pisa and INFN, Pisa S. Bettoni CERN, Geneva M. E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma)
	The vertical focusing element closest to the interaction point of the SuperB factory based on the large crossing angle collision scheme (~50 mrad), must provide a pure quadrupolar field on each of the two beams. This allows to avoid the high background rate in the detector which would be produced by the over-bend of the off-energy particles if a dipolar component were present. Because of the small separation of the two beams in the transverse dimension (only 2 cm) the influence of each winding on the other one is not negligible and, for the same space limitation, a multi-layer configuration is not suitable to compensate the high order multipoles. A novel design, based on 'helical-type' windings, has therefore been investigated. The windings generates the pure quadrupolar field as a superposition of the inner field of the surrounding coil and of the outer fringe field of the neighbor one. The same idea may be used to produce two pure quadrupolar fields with opposite strength, suitable for the final focus elements in colliders, as LHC, where the sign of the circulating particles are the same. In this paper the 2D concept and the 3D model of this design are presented.
WEPD003	Manufacture and Test of a Small Ceramic-insulated Nb3Sn Split Solenoid	2404
	B. Bordini, R. Maccaferri, L. Rossi, D. Tommasini CERN, Geneva
	A small split solenoid wound with high Jc Nb3Sn conductor, constituted by a 0.8 mm Rod Re-stack Process (RRP) strand, was built and tested at CERN in order to study the applicability of: ceramic wet glass braid insulation without epoxy impregnation of the magnet; a new heat treatment devised at CERN and particularly suitable for reacting RRP Nb3Sn strands. This paper briefly describes the solenoid and the experimental results obtained during 4.4 K and 1.9 K tests. The split solenoid consists of two coils (25 mm inner diameter, 51.1 mm outer diameter, 12.9 mm height). The coils were initially separately tested, in an iron mirror configuration, and then tested together in split solenoid configuration. In all the tests at 4.4 K the coils reached a current higher than 97% of their short sample limits at the first quench; in split solenoid configuration the maximum field in the coils and in the aperture were respectively 10.7 T and 12.5 T. At 1.9 K the coils had premature quenches due to self field instability despite the rather high RRR of the two coils (190 and 270). This phenomenon at 1.9 K, expected by our theory* and also confirmed by strand measurements, is discussed. *B. Bordini, E. Barzi, S. Feher, L. Rossi, and A. V. Zlobin. "Self-Field Effects in Magneto-Thermal Instabilities for Nb-Sn Strands," to be published in IEEE Trans. Appl. Supercond. 2008.
WEPD005	Scaling Laws for Magnetic Energy in Superconducting Quadrupoles	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%.
WEPD006	Conceptual Design of Superferric Magnets for PS2	2410
	L. Bottura, G. De Rijk, M. Karppinen, G. Kirby, R. Maccaferri, C. Maglioni, V. Parma, L. Rossi, W. Scandale, L. Serio, D. Tommasini CERN, Geneva
	We analyze feasibility and cost of a superferric magnet design for the PS2, the novel 50 GeV ring that should replace the PS in the CERN injector chain. Specifically, we provide the conceptual design of dipole and quadrupoles, including considerations on cryogenics and powering. The magnets have warm iron yoke, and cryostated superconducting coils embedded in the magnet, which reduces AC loss at cryogenic temperature. The superconductor has large operating margin to endure beam loss and operating loads over a long period of time. Although conservative, and without any critical dependence on novel technology developments, this superconducting option appears to be attractive as a low-power alternative to the normal-conducting magnets that are the present baseline for the PS2 design. In addition it provides flexibility in the selection of flat-top duration at no additional cost.
WEPD007	Detection and Location of Electrical Insulation Faults on the LHC Superconducting Circuits during the Hardware Commissioning	2413
	D. Bozzini, V. Chareyre, K. H. Mess, S. Russenschuck CERN, Geneva
	As part of the electrical quality assurance program, all superconducting circuits of the LHC have to be subjected to a (high) DC voltage, up to 1.9 kV DC, for the testing of the electrical insulation. Circuits with an insulation fault have to be repaired before powering. Fault location within a ± 3 m range over the total length of 2700 m has been achieved in order to limit the number of interconnection openings. In this paper, the methods, tooling, and procedures for the detection and location of electrical faults will be presented in view of the practical experience gained in the LHC tunnel. Three cases of faults detected and localized during the hardware commissioning phases of the LHC will be discussed.
WEPD008	Automatic System for the DC High Voltage Qualification of the Superconducting Electrical Circuits of the LHC Machine	2416
	D. Bozzini, V. Chareyre, S. Russenschuck CERN, Geneva M. Bednarek, P. Jurkiewicz, A. Kotarba, J. Ludwin, S. Olek HNINP, Kraków
	A system has been developed to verify automatically with the application of a DC high voltage, the insulation resistance between circuits to circuit and circuit to ground. In the most complex case of the LHC machine up to 72 circuits share the same volume inside the cryogenic lines and each circuit can have an insulation fault versus any other circuit or versus ground. The system can connect up to 80 circuits and apply a voltage up to 2 kV DC. The leakage of current flowing through each circuit is measured within a range of 1 nA to 2 mA. The matrix of measurements characterizes the paths taken by the currents and recognizes weak points of the insulation between circuits. The system is composed of a DC voltage source, a data acquisition card that measures with precision currents and voltages and drives up to 5 high voltage switching modules offering each 16 channels. A LabVIEW based application controls the system for an automatic and safe operation. This paper describes the hardware and software design, the testing methodology and the results obtained during the qualification of the LHC superconducting circuits.
WEPD009	The CERN High Field Magnet Program	2419
	G. De Rijk CERN, Geneva
	With the LHC, magnets of 10T peak field Nb-Ti technology were developed and this technology reached full maturity. The next step in field level, with a peak field in the range of 15T, will be needed for the LHC phase II upgrade. For this upgrade the temperature margin and radiation resistance of the Nb-Ti coil technology is not sufficient. Begin 2008 CERN starts a program to develop high field magnets for LHC upgrades and other future programs. For this mostly Nb3Sn conductors will be employed but also HTS conductors will be considered. In this paper an overview will be presented of the projects for which this HFM technology will be needed. The the program will be presented in terms of R&D chapters and work packages. The need and opportunities for collaborations with other institutes will be discussed.
WEPD010	Electronic Systems for the Protection of Superconducting Devices in the LHC	2422
	R. Denz, K. Dahlerup-Petersen, K. H. Mess CERN, Geneva
	The Large Hadron Collider LHC incorporates an unprecedented amount of superconducting components: magnets, bus-bars, and current leads. Most of them require active protection in case of a transition from the superconducting to the resistive state, the so-called quench. The electronic systems ensuring the reliable quench detection and further protection of these devices have been developed and produced over the last years and are currently being put into operation. The paper will describe the various protection devices and hereby focus on the final test and commissioning phase of the system. First results from operation will be presented as well as an analysis of the system performance.
WEPD011	Development Work for a Short Curved Superconducting Dipole Magnet for the HESR at FAIR	2425
	F. M. Esser, R. Greven, G. Hansen, F. Klehr, J. Schillings, H. Soltner, R. Tölle FZJ, Jülich
	Forschungszentrum Juelich has taken the leadership of a consortium being responsible for the design of the High-Energy Storage Ring (HESR) going to be part of the FAIR project at GSI. Within these activities a design for a short cosine-theta superconducting dipole has been carried out together with industry partners. Its length will be approximately one third of the original HESR dipole whereas all other design parameter will be the same. The main design criterion is the short bending radius of 15.3 m of the magnet implying that the coil itself has a curved shape. Beside the geometrical design of the cold mass, this paper will focus particularly on the finite element calculations from the assembly through the cool down to the operating temperature of the magnet. First manufacturing tests as well as a status report on the achievements so far will be presented and future plans will be discussed.
WEPD012	The LHC Continuous Cryostat Interconnections: the Organization of a Logistically Complex Worksite Requiring Strict Quality Standards and High Output	2428
	P. Fessia, F. F. Bertinelli, D. Bozzini, P. Cruikshank, A. Jacquemod, W. Maan, A. Musso, L. Oberli, A. Poncet, S. Russenschuck, F. Savary, M. Struik, Z. Sulek, J.-P. G. Tock, D. Tommasini, C. Vollinger CERN, Geneva A. Grimaud ALL43, Saint-Genis-Pouilly A. Kotarba HNINP, Kraków L. Vaudaux IEG, St-Genis-Pouilly
	The interconnections of the Large Hadron Collider (LHC) continuous cryostat have been completed in autumn 2007: 1695 magnet to magnet interconnections and 224 interconnections between the continuous cryostat and the cryogenic distribution line have been closed along the 27km of the LHC. The high productivity demanded, the complexity of the interconnection sequence, the strict quality standards have required an ad hoc organization in order to steer and coordinate the activities on a worksite that was spread along the whole accelerator ring. The optimization of the intricate sequence of construction and test phases carried out by CERN staff, CERN collaborating institutes and contractors have led to the necessity of a common approach and of a very effective information flow. Specialized CERN teams have been created to deal with non standard operation to smooth the work sequences of the main assembly teams. In this paper, after having recalled the main technical challenges, we review the organizational choices that have been taken, their impact on quality and productivity and we briefly analyze the development of the worksite in term of allocated resources and production.
WEPD013	Four-Coil Superconducting Helical Solenoid Model for Muon Beam Cooling	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.
WEPD014	Magnets for the MANX 6-D Muon Cooling Demonstration Experiment	2434
	V. S. Kashikhin, N. Andreev, V. Kashikhin, M. J. Lamm, K. Yonehara, A. V. Zlobin Fermilab, Batavia, Illinois M. Alsharo'a, R. P. Johnson, S. A. Kahn, T. J. Roberts Muons, Inc, Batavia
	MANX is a 6-dimensional muon ionization-cooling experiment that has been proposed to Fermilab to demonstrate the use of a helical cooling channel (HCC) for muon beam emittance reduction for future muon colliders and neutrino factories. The HCC for MANX has solenoidal, helical dipole, and helical quadrupole magnetic components, which diminish as the beam loses energy as it slows down in the liquid helium absorber inside the magnet. The proposed magnet system design is comprised of coil rings positioned along a helical path, which will provide the desired solenoidal and helical dipole and quadrupole fields. Additional magnets that provide emittance matching between the HCC and the upstream and downstream spectrometers are also described. The results of a G4Beamline simulation of the beam cooling behavior of the magnet and absorber system will be presented.
WEPD015	Design Studies of Magnet Systems for Muon Helical Cooling Channels	2437
	V. Kashikhin, V. S. Kashikhin, M. J. Lamm, M. L. Lopes, A. V. Zlobin Fermilab, Batavia, Illinois M. Alsharo'a, R. P. Johnson, S. A. Kahn Muons, Inc, Batavia
	Helical cooling channels consisting of a magnet system with superimposed solenoid, helical dipole and quadrupole fields, and a pressurized gas absorber in the aperture, promise high efficiency in providing 6D muon beam cooling for a future Muon Collider and some other applications. Two alternative designs of the magnet system for the helical cooling channel are being investigated at the present time. The first one is based on a straight, large aperture solenoid with helical dipole and quadrupole coils. The other one is based on a spiral solenoid which generates the main solenoid field and the helical dipole and quadrupole components. Both concepts have been developed and compared for the MANX experiment. In this paper we continue design studies and comparison of these two concepts for the high field sections of a helical cooling channel. The results of magnetic and mechanical analysis as well as the superconductor choice and specifications will be presented and discussed.
WEPD016	Electrical Quality Assurance of the Superconducting Circuits during LHC Machine Assembly	2440
	S. Russenschuck, D. Bozzini, V. Chareyre, O. Desebe, K. H. Mess CERN, Geneva M. Bednarek, D. P. Dworak, E. Gornicki, P. Jurkiewicz, P. J. Kapusta, A. Kotarba, J. Ludwin, S. Olek, M. Talach, M. Zieblinski HNINP, Kraków M. Klisch, B. Prochal AGH, Cracow
	Based on the LHC powering reference database, all-together 1712 superconducting circuits have been electrically wired and interconnected in the various cryogenic lines of the LHC machine. Continuity, magnet polarity, and the quality of the electrical insulation have been the main objectives of the Electrical Quality Assurance (ELQA) activities during the LHC machine assembly. Another activity aimed at ensuring the coherence between the reference database on one side, and the polarity conventions used for beam simulation and magnetic measurements. With the assembly of the LHC now completed, the paper reviews the methods and procedures established for the ELQA, as well as the employed time and resources. The qualification results will be presented with the emphasis on the detected electrical non-conformities and their possible impact on the performance of the LHC machine.
WEPD017	Full Size Prototype Magnets for Heavy Ion Superconducting Synchrotron SIS100 at GSI: Status of Manufacturing and Test at JINR	2443
	A. D. Kovalenko, N. N. Agapov, A. V. Alfeev, A. V. Bychkov, A. V. Gromov, H. G. Khodzhibagiyan, G. L. Kuznetsov, A. Y. Starikov JINR, Dubna, Moscow Region E. S. Fischer, G. Moritz, P. J. Spiller GSI, Darmstadt A. V. Shabunov JINR/LHE, Moscow
	The SIS100 synchrotron is designed for acceleration of high intensity beams with a pulse repetition rate of 1 Hz. The use of superferric Nuclotron-type dipoles, quadrupoles and corrector magnets is planned in the accelerator magnetic system. The magnet coils are made of hollow NbTi composite cable cooled with two-phase helium flow at 4.5 K. The lattice comprises 108 dipoles, 168 quadrupoles and necessary set of steerer and multipole corrector magnets. We present recent results from the design and optimization of the SIS100 magnetic elements parameters. The status of manufacturing full size prototypes is presented. The essential features of the magnets production and the new test results are discussed.
WEPD018	Commissioning of the LHC Current Leads	2446
	A. Ballarino, S. A. March, K. H. Mess CERN, Geneva
	The powering of the LHC superconducting magnets relies on more than 3000 leads transporting the current from/to the cryogenic environment and rated at currents ranging from 60 A to 13000 A. The design of these leads, about 1000 of which are based on high temperature superconducting material, was entirely done at CERN, where prototype assemblies were also assembled and tested, while the series production was done in external laboratory and companies on the basis of build-to-print specification. This report summarizes the results of the tests performed during the commissioning of the LHC machine, when the leads underwent the thermal and electrical cycles necessary for the powering of the LHC superconducting circuits.
WEPD020	Stability of Superconducting Wire in Magnetic Field	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.
WEPD021	Magnetic Field Characteristics of a SIS 100 Full Size Dipole	2452
	P. Schnizer, E. S. Fischer GSI, Darmstadt P. G. Akishin JINR, Dubna, Moscow Region R. V. Kurnyshov Electroplant, Moscow B. Schnizer TUG/ITP, Graz P. A. Shcherbakov IHEP Protvino, Protvino, Moscow Region G. Sikler, W. Walter BNG, Würzburg
	FAIR will feature two superconducting fast ramped synchrotrons. The dipole magnets for one of them, SIS 100, have been designed and prototypes were built. The properties of the magnetic field were analysed using OPERA (for DC operation) and ANSYS for dynamic calculations. Elliptic multipoles fulfilling the Laplace Equation in plane elliptic coordinates describe the field within the whole aperture consistently within a single expansion. Further circular multipoles, valid within the ellipse, can be calculated analytically from the elliptic multipoles. The advantage of this data representation is illustrated on the FEM calculation performed for SIS 100 dipoles and quadrupoles currently foreseen for the machine. The magnetic field of one of these prototypes was measured using a mole. We compare the results of the calculation to the measurement for the static as well as the dynamic mode.
WEPD022	High Field Superconductor for Muon Cooling	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	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.
WEPD025	A Feasibility Study of Superconducting Dipole for the Early Separation Scheme of SLHC	2461
	G. Sterbini, D. Tommasini CERN, Geneva
	In the framework of the LHC luminosity upgrade an early separation scheme is being studied for the final phase (L~10³⁵ cm^-2 s^-1 with substantial changes in the IR). In this paper we compare a Nb3Sn and a Nb-Ti cos(θ) design: the aim is to explore the benefits and the limits of a compact solution with respect to the detector's constraints and the energy deposition issues. We propose to put the dipole system (cryostat and magnet) at a location starting at 6.8 m from the IP. The preliminary cross section, the achievable integrated field, the energy deposition on the magnet are presented and discussed.
WEPD026	The Special LHC Interconnections: Technologies, Organization and Quality Control	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	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.
WEPD028	Performance of the Superconducting Corrector Magnet Circuits during the Commissioning of the LHC	2470
	W. Venturini Delsolaro, V. Baggiolini, A. Ballarino, B. Bellesia, F. Bordry, A. Cantone, M. P. Casas Lino, C. CastilloTrello, N. Catalan-Lasheras, Z. Charifoulline, C. Charrondiere, G. D'Angelo, K. Dahlerup-Petersen, G. De Rijk, R. Denz, M. Gruwe, V. Kain, M. Karppinen, B. Khomenko, G. Kirby, S. L.N. Le Naour, A. Macpherson, A. Marqueta Barbero, K. H. Mess, M. Modena, R. Mompo, V. Montabonnet, D. Nisbet, V. Parma, M. Pojer, L. Ponce, A. Raimondo, S. Redaelli, V. Remondino, H. Reymond, A. Rijllart, R. I. Saban, S. Sanfilippo, K. M. Schirm, R. Schmidt, A. P. Siemko, M. Solfaroli Camillocci, H. Thiesen, Y. Thurel, A. Vergara-Fernández, A. P. Verweij, R. Wolf, M. Zerlauth CERN, Geneva A. Castaneda, I. Romera Ramirez CIEMAT, Madrid SF. Feher, R. H. Flora Fermilab, Batavia, Illinois
	The LHC is a complex machine requiring more than 7400 superconducting corrector magnets distributed along a circumference of 26.7 km. These magnets are powered in 1380 different electrical circuits with currents ranging from 60 A up to 600 A. Among the corrector circuits the 600 A corrector magnets form the most diverse and differentiated magnet circuits. About 60000 high current connections had to be made. A minor fault in a circuit or one of the superconducting connections would have severe consequences for the accelerator operation. All magnets are wound from various types of Nb-Ti superconducting strands, and many contain resistors to by-pass the current in case of the transition to the normal conducting state in case of a quench, and hence reduce the hot spot temperature. In this paper the performance of these magnet circuits is presented, focussing on the quench current and quench behaviour of the magnets. Quench detection and the performance of the electrical interconnects will be dealt with. The results as measured on the entire circuits will be compared to the test results obtained during the reception tests of the individual magnets.
WEPD029	Performance of the Main Dipole Magnet Circuits of the LHC during Commissioning	2473
	A. P. Verweij, V. Baggiolini, A. Ballarino, B. Bellesia, F. Bordry, A. Cantone, M. P. Casas Lino, A. Castaneda, C. CastilloTrello, N. Catalan-Lasheras, Z. Charifoulline, G.-J. Coelingh, G. D'Angelo, K. Dahlerup-Petersen, G. De Rijk, R. Denz, M. Gruwe, V. Kain, B. Khomenko, G. Kirby, S. L.N. Le Naour, A. Macpherson, A. Marqueta Barbero, K. H. Mess, M. Modena, R. Mompo, V. Montabonnet, D. Nisbet, V. Parma, M. Pojer, L. Ponce, A. Raimondo, S. Redaelli, H. Reymond, D. Richter, A. Rijllart, I. Romera, R. I. Saban, S. Sanfilippo, R. Schmidt, A. P. Siemko, M. Solfaroli Camillocci, H. Thiesen, Y. Thurel, W. Venturini Delsolaro, A. Vergara-Fernández, R. Wolf, M. Zerlauth CERN, Geneva SF. Feher, R. H. Flora Fermilab, Batavia, Illinois
	During hardware commissioning of the Large Hadron Collider, 8 main dipole circuits and 16 main quadrupole circuits are tested at 1.9 K and up to their nominal current. Each dipole circuit contains 154 magnets of 15 m length, and has a total stored energy of up to 1.1 GJ. Each quadrupole circuit contains 47 or 51 magnets of 5.4 m length, and has a total stored energy of up to 20 MJ. All magnets are wound from Nb-Ti superconducting Rutherford cables, and contain heaters to quickly force the transition to the normal conducting state in case of a quench, and hence reduce the hot spot temperature. In this paper the performance of these circuits is presented, focusing on the quench current and quench behaviour of the magnets. Quench detection, heater performance, operation of the cold bypass diodes, cryogenic recovery time, electrical joints, and possible magnet-to-magnet quench propagation will be dealt with. The results as measured on the entire circuits will be compared to the test results obtained during the reception tests of the individual magnets.
WEPD030	Feasibility Study of Combined Function Magnets for a NS-FFAG for Medical Applications	2476
	H. Witte, J. H. Cobb OXFORDphysics, Oxford, Oxon K. J. Peach JAI, Oxford
	Non-scaling fixed field alternating gradient (NS-FFAG) accelerators combine a number of advantages, such as rapid particle acceleration and large acceptance. These features make NS-FFAGs particularly interesting for medical applications. NS-FFAGs could be used for cancer therapy, which may lead to significant size and cost reductions in comparison to other accelerator types. Cancer therapy with protons or carbon ions is advantageous in comparison to conventional radiation treatment amongst other things due to the higher biological effectiveness. This paper discusses the basic magnet design issues for the PAMELA project. PAMELA is a prototype proton/carbon-ion therapy facility.
WEPD031	Dependence of the Static and Dynamic Field Quality of the LHC Superconducting Dipole Magnets on the Pre-cycle Ramp Rate	2479
	N. J. Sammut, L. Bottura, G. Deferne, W. Venturini Delsolaro, R. Wolf CERN, Geneva N. J. Sammut University of Malta, Faculty of Engineering, Msida
	The allowed multipoles in the Large Hadron Collider (LHC) superconducting dipole magnets decay whilst on a constant current plateau. It is known that the decay amplitude is largely affected by the powering history of the magnet, and particularly by the pre-cycle flat top current and duration and the pre-injection preparation duration. Recently, it was observed that the decay amplitude is also highly dependent on the pre-cycle ramp rate, which has an indirect effect also on the sample of data taken at constant field along the magnet loadlines. This is an important consideration to be included in the Field Description for the LHC (FiDeL), to cope with the difference between the test procedure followed for series tests and the expected cycles during the machine operation. This paper presents the results of the measurements performed to investigate this phenomenon and describes the method included in FiDeL to represent this dependence.
WEPD033	A Demonstration Experiment for the Forecast of Magnetic Field and Field Errors in the Large Hadron Collider	2482
	N. J. Sammut, R. Alemany-Fernandez, L. Bottura, G. Deferne, M. Lamont, J. Miles, S. Sanfilippo, M. Strzelczyk, W. Venturini Delsolaro, P. Xydi CERN, Geneva N. J. Sammut University of Malta, Faculty of Engineering, Msida
	In order to reduce the burden on the beam-based feedback, the Large Hadron Collider (LHC) control system is embedded with the Field Description for the LHC (FiDeL) which provides a forecast of the magnetic field and the multipole field errors. FiDeL has recently been extensively tested at CERN to determine main field tracking, multipole forecasting and compensation accuracy. In this paper we describe the rationale behind the tests, the procedures employed to characterize and power the main magnets and their correctors, and finally, we present the results obtained. We also give an indication of the prediction accuracy that the system can deliver during the operation of the LHC and we discuss the implications that these will have on the machine performance.
WEPD034	Main Field Tracking Measurement in the LHC Superconducting Dipole and Quadrupole Magnets	2485
	P. Xydi, R. Alemany-Fernandez, L. Bottura, G. Deferne, M. Lamont, J. Miles, R. Mompo, M. Strzelczyk, W. Venturini Delsolaro CERN, Geneva N. J. Sammut University of Malta, Faculty of Engineering, Msida
	One of the most stringent requirements during the energy ramp of the Large Hadron Collider (LHC) is to have a constant ratio between dipole-quadrupole and dipole-dipole field so as to control the variation of the betatron tune and of the beam orbit throughout the acceleration phase, hence avoiding particle loss. To achieve the nominal performance of the LHC, a maximum variation of ±0.003 tune units can be tolerated. For the commissioning with low intensity beams, acceptable bounds are up to 30 times higher. For the quadrupole-dipole integrated field ratio, the above requirements translate in the tight windows of 6 ppm and 180 ppm, while for dipole differences between sectors the acceptable error is of the order of 10^-4. Measurement and control at this level are challenging. For this reason we have launched a dedicated measurement R&D to demonstrate that these ratios can be measured and controlled within the limits for machine operation. In this paper we present the techniques developed to power the magnets during the current ramps, the instrumentation and data acquisition setup used to perform the tracking experiments, the calibration procedure and the data reduction employed.
WEPD036	Radiation and Thermal Analysis of Superconducting Quadrupoles in the Interaction Region of Linear Collider	2488
	A. V. Zlobin, A. I. Drozhdin, V. Kashikhin, V. S. Kashikhin, M. L. Lopes, N. V. Mokhov Fermilab, Batavia, Illinois A. Seryi SLAC, Menlo Park, California
	The upcoming and disrupted electron and positron beams in the baseline design of ILC interaction region are focused by compact FD doublets each consisting of two small-aperture superconducting quadrupoles and multipole correctors. These magnets will work in a severe radiation environment generated primarily by incoherent pairs and radiative Bhabhas. This paper analyzes the radial, azimuthal and longitudinal distributions of radiation heat deposition in incoming and disrupted beam doublets. Operation margins of baseline quadrupoles based on NbTi superconductor and direct wind technology as well as alternative designs based on NbTi or Nb3Sn Rutherford cables are calculated and compared. The possibilities of reducing the heat deposition in magnet coils using internal absorbers are discussed.
WEPD037	Nb3Sn Quadrupoles in the LHC IR Phase I Upgrade	2491
	A. V. Zlobin, J. A. Johnstone, V. Kashikhin, N. V. Mokhov, I. L. Rakhno Fermilab, Batavia, Illinois S. Peggs, G. Robert-Demolaize, P. Wanderer, R. de Maria BNL, Upton, Long Island, New York
	After some years of operation at nominal parameters, the LHC will be upgraded for higher luminosity. At the present time it is planned to perform the IR upgrade in two phases with the target luminosity for Phase I of ~2.5· 10³⁴ cm^-2s^-1 and up to 10³⁵ cm^-2s^-1 for Phase II. In Phase I the baseline 70-mm NbTi low-beta quadrupoles will nominally be replaced with larger aperture NbTi magnets and in Phase II with higher performance Nb3Sn magnets. U. S.-LARP is working on the development of large aperture high-performance Nb3Sn magnet technologies for the LHC Phase II luminosity upgrade. Recent progress also suggests the possibility of using Nb3Sn quadrupoles in the Phase I upgrade, improving the luminosity through an early demonstration of Nb3Sn magnet technology in a real accelerator environment. This paper discusses the possible hybrid optics layouts for Phase I upgrades with both NbTi and Nb3Sn quadrupoles, introducing magnet parameters and issues related to using Nb3Sn quadrupoles including magnet length and aperture limitations, field quality, operation margin, etc. Possible transition scenarios to Phase II are also discussed.
WEPP005	Measurements and Effects of the Magnetic Hysteresis on the LHC Crossing Angle and Separation Bumps	2530
	N. J. Sammut, H. Burkhardt, C. Giloux, W. Venturini Delsolaro, S. M. White CERN, Geneva N. J. Sammut University of Malta, Faculty of Engineering, Msida
	The superconducting orbit corrector magnets (MCBC and MCBY) in the Large Hadron Collider (LHC) at CERN will be used to generate parallel separation and crossing angles at the interaction points during the different phases that will bring the LHC beams into collision. However, the field errors generated by the inherent hysteresis in the operation region of the orbit correctors may lead to unwanted orbit perturbations that could have a critical effect on luminosity. This paper presents the results obtained from dedicated cryogenic measurements on the orbit correctors from the simulated results on the impact of the hysteresis on the LHC orbit.