EPAC 2006 - Classification:07 Accelerator Technology/T10 Superconducting Magnets

07 Accelerator Technology

T10 Superconducting Magnets

Paper	Title	Page
WEPLS064	Wiggler for ILC Cooler	2526
	A.A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York
	We represented the concept of a wiggler with linear piecewise field dependence. This eliminates nonlinearities in wiggler. This type of wiggler can be recommended for usage in ILC cooler.
WEPLS087	Status of the Development of the FAIR Superconducting Magnets	2577
	G. Moritz GSI, Darmstadt
	For the planned 'Facility for Antiprotons and Ion Research' (FAIR), a variety of superconducting magnets is foreseen. The synchrotrons SIS 100 and SIS 300 will use fast-pulsed superferric and superconducting cos (theta) magnets. The storage ring CR and the SuperFRS will be equipped with large-scale superferric magnets, while in the storage ring HESR RHIC-type magnets are foreseen. The status of the R&D activities will be presented.
WEPLS089	Feasibility Study of a Permanent Magnet Made from High-Tc Bulk Superconductor	2580
	M. Masuzawa, K. Egawa, K. Tsuchiya KEK, Ibaraki
	A field trapping experiment using a magnetic field up to ~1.5 T was performed using high-Tc bulk superconductors. Applications of bulk high-Tc superconductors have been investigated in various fields. High-Tc superconductors are attractive since they can trap higher magnetic fields than conventional permanent magnets. The trapping experiment was done with a field of above 1 T, which can be easily produced by conventional magnets. However, achieving the desired field distribution and understanding the characteristics of the trapped field and its decay process would open up the possibility of high-Tc bulk superconductor applications in the design of magnets for particle accelerators The distribution of the trapped field and its decay process was monitored by an array of Hall sensors for different shapes of the bulk superconductors. The observations are reported on in this paper.
WEPLS090	Full Length Superferric Dipole and Quadrupole Prototype Magnets for the SIS100 at GSI: Status of the Design and Manufacturing	2583
	A.D. Kovalenko, N.N. Agapov, A.V. Alfeev, H.G. Khodzhibagiyan, G.L. Kuznetsov, V.V. Seleznev, A.Y. Starikov JINR, Dubna, Moscow Region E. Fischer, G. Moritz, C. Muehle, P.J. Spiller GSI, Darmstadt A.K. Kalimov St. Petersburg State Polytechnic University, St. Petersburg A.V. Shabunov JINR/LHE, Moscow
	The SIS100, one of the two basic accelerators of the future Facility for Antiproton and Ion Research FAIR at GSI, should provide acceleration of U²⁸⁺ and proton beams for 0.5 s with a pulse repetition rate of 1 Hz. In the accelerator magnetic system superferric 2 T dipoles of about 3 m length and 35 T/m quadrupoles of about 1 m length will be used. The magnet coils are made from hollow NbTi composite cable cooled with two-phase helium flow at 4.5 K. The maximum operating current of 7500 A is supposed. The lattice comprises 108 dipoles and 168 quadrupoles. The elliptic beam pipe inner sizes have been fixed to 130x60 mm2 for the dipole and 135x65 mm2 for the quadrupole The design approach is based on the improved versions of the Nuclotron fast-cycling magnets that provide significant less AC loss at 4.5 K, better quality of the magnetic field and a higher long-term mechanical stability of the magnet coils. The AC losses in the magnets for the strongest SIS100 operating cycle at 4.5 K are expected to be about 13 W/m and 17 W/m in the full length prototype dipole and quadrupole magnets respectively.
WEPLS091	Analysis of the Superferric Quadrupole Magnet Design for the SIS100 Accelerator of the FAIR Project	2586
	E. Fischer, G. Moritz GSI, Darmstadt H.G. Khodzhibagiyan, A.D. Kovalenko JINR, Dubna, Moscow Region R.V. Kurnyshov, P.A. Shcherbakov IHEP Protvino, Protvino, Moscow Region
	The heavy ion fast-cycling synchrotron SIS100 is the "workhorse", of the future Facility for Antiproton and Ion Research FAIR at GSI in Darmstadt. The main lattice parameters of the accelerator are defined now so the main engineering problems of the new superferric magnets should be analyzed and solved too. We present the results of finite element calculations and compare them with the experimental data from investigation of the model magnets to characterize the expected AC loss properties of the full length prototype quadrupole. We discuss the appropriate new coil structure aimed at minimizing the heat releases at 4.5 K, but providing the requested long-term mechanical stability against dynamic Lorentz forces and thermal cooling cycles as well.
WEPLS092	Computer Modeling of Magnetic System for C400 Superconducting Cyclotron	2589
	Y. Jongen, D. Vandeplassche, S.E. Zaremba IBA, Louvain-la-Neuve G.A. Karamysheva, N.A. Morozov, E. Samsonov JINR, Dubna, Moscow Region
	The superconducting cyclotron (C400) is designed at IBA (Belgium) able to accelerate carbon ions at 400 MeV/nucleon. By computer simulation with 3D TOSCA code, the cyclotron magnetic system principal parameters were estimated (pole radius 187 cm, outer diameter 606 cm, valley depth 60 cm, height 276 cm). The required isochronous magnetic field was shaped with an accuracy of ± 2 mT. Four-fold symmetry and spiralized sectors with elliptical gap (minimal 12 mm at extraction) provide the stable beam acceleration till 15 mm from the pole edge.
WEPLS093	3D Field Computation for the Main Prototype Magnets of the SIS100 Accelerator of the FAIR Project	2592
	P.A. Shcherbakov IHEP Protvino, Protvino, Moscow Region E. Fischer GSI, Darmstadt R.V. Kurnyshov Electroplant, Moscow
	Fast cycling superferric magnets are planned for use in the new international accelerator Facility for Antiprotons and Ion Research (FAIR) at GSI, Darmstadt. The dipoles and quadrupoles have to provide the required field quality from the injection field of 0.25T and 4.3T/m up to the maximum values of 2.1T and 35T/m respectively. The complex 3D magnetic field distribution due to the longitudinal component Bz near the yoke end regions and the presence of eddy currents also in the bulk construction elements as well as in a mechanical stable beam pipe design can create unacceptable static and dynamic nonlinearities. The detailed knowledge of these effects is necessary to control the field quality for all operating cycles to be provided by the SIS100 accelerator. We discuss the methodical problems of 3D finite element calculations (ANSYS) of the local and the integral nonlinearities, considering also the problems caused by the various nonlinear and anisotropic material properties and by the structure elements of the yoke and beam pipe. The calculated integral static and the affected by eddy currents harmonic coefficients are presented.
WEPLS094	3D Magnetic Field and Eddy Current Loss Calculations for Iron Dominated Accelerator Magnets using ANSYS Compared with Results of Noncommercial Codes	2595
	P.A. Shcherbakov IHEP Protvino, Protvino, Moscow Region E. Fischer GSI, Darmstadt R.V. Kurnyshov Electroplant, Moscow
	The design of fast ramped superferric magnets with repetition rates in the order of 1Hz requires reliable software tools to calculate the complex 3D magnetic field quality as well as the impact of eddy current and hysteresis loss. Various technological construction details should be taken into account to obtain a high field quality. We present a methodical study of these questions based on ANSYS calculations for simplified dipole models. The details of these analysis are compared with recently published results obtained by different special codes, i.e. an integral and the FIT method. The time dependences of eddy current power due to longitudinal magnetic field component at the yoke ends, the transient field distribution in the yoke volume and the total eddy current loss are investigated, choosing the identical geometry with the same magnetic and electric properties of the lamination steel used by the other codes. The conclusions for the application potential of the different methods are discussed.
WEPLS096	Design and Calculation of a Superferric Combined Magnet for XFEL	2598
	F. Toral, P. Abramian, J.L. Gutierrez, E. Rodriguez, I. Rodriguez, S. Sanz, C. Vazquez CIEMAT, Madrid R. Bandelmann, H. Brueck DESY, Hamburg J. Calero, L. García-Tabarés CEDEX, Madrid J. Lucas Elytt Energy, Madrid
	A planned European X-ray Free Electron Laser so-called XFEL is being developed within the framework of an international collaboration. The design and fabrication of a prototype of a combined magnet is part of the Spanish contribution to this project. This magnet consists of a superferric quadrupole for focusing and two dipoles (horizontal and vertical) for steering, glued around the beam tube. The magnet will be operated in a superfluid helium bath. The aperture is 78 mm. The quadrupole gradient is 35 T/m whereas each dipole field is about 0.04 T. The magnetic saturation is limited to 5% at nominal current, which is quite a challenging specification for such aperture and gradient. As the overall length of the helium vessel is just 300 mm, the calculation of the magnetic field is a pure 3-D problem which has been solved and optimized using two different FEM codes to cross-check the results. This paper also gives some guidelines about the fabrication techniques most suitable for the first prototype, which is now under construction.
WEPLS097	Random Errors in Superconducting Dipoles	2601
	B. Bellesia, E. Todesco CERN, Geneva C. Santoni Université Blaise Pascal, Clermont-Ferrand
	The magnetic field in a superconducting magnet is mainly determined by the position of the conductors. Hence, the main contribution to the random field errors comes from random displacement of the coil with respect to its nominal position. Using a Monte-Carlo method, we analyze the measured random field errors of the main dipoles of the LHC, Tevatron, RHIC and HERA projects in order to estimate the precision of the conductor positioning reached during the production. The method can be used to obtain more refined estimates of the random components for future projects.
WEPLS098	Experience with the Quality Assurance of the Superconducting Electrical Circuits of the LHC Machine	2604
	D. Bozzini, V. Chareyre, K.H. Mess, S. Russenschuck CERN, Geneva A. Kotarba, S. Olek HNINP, Kraków
	The coherence between the powering reference database and the Electrical Quality Assurance (ELQA) is guaranteed on the procedural level. However, a challenge remains the coherence between the database, the magnet test and assembly procedures, and the connection of all superconducting circuits of the LHC. In this paper, the methods, tooling, and procedures for the ELQA during the assembly phase of the LHC will be presented in view of the practical experience gained in the LHC tunnel. The parameters measured at ambient temperature such as the dielectric insulation and the impedance transfer function of assembled circuits will be discussed. Some examples of detected polarity errors and the treatment of non-conformities will be presented.
WEPLS099	Fault Detection and Identification Methods Used for the LHC Cryomagnets and Related Cabling	2607
	D. Bozzini, F. Caspers, V. Chareyre, Y. Duse, T. Kroyer, R. Lopez, A. Poncet, S. Russenschuck CERN, Geneva
	Several non-standard methods for electrical fault location have been successfully developed and tested. As part of the electrical quality assurance program, certain wires have to be subjected to a (high) DC voltage for the testing of the insulation. With the time difference of spark-induced electromagnetic signals measured with an oscilloscope, fault localization within a ± 10 cm range has been achieved. Another method used and adapted for the particular needs, was the synthetic pulse time-domain reflectometry (TDR) by means of a vector network analyzer. This instrument has also been applied as a low frequency sweep impedance analyzer in order to measure fractional capacities of cable assemblies where TDR was not applicable.
WEPLS100	Performance of LHC Main Dipoles for Beam Operation	2610
	G. De Rijk, M. Bajko, L. Bottura, M.C.L. Buzio, V. Chohan, L. Deniau, P. Fessia, J. Garcia Perez, P. Hagen, J.-P. Koutchouk, J. Kozak, J. Miles, M. Missiaen, M. Modena, P. Pugnat, V. Remondino, L. Rossi, S. Sanfilippo, F. Savary, A.P. Siemko, N. Smirnov, A. Stafiniak, E. Todesco, D. Tommasini, J. Vlogaert, C. Vollinger, L. Walckiers, E.Y. Wildner CERN, Geneva
	At present about 75% of the main dipoles for the LHC have been manufactured and one of the three cold mass assemblers has already completed the production. More than two third of the 1232 dipoles needed for the tunnel have been tested and accepted. In this paper we mainly deal with the performance results: the quench behavior, the magnetic field quality, the electrical integrity quality and the geometry features will be summarized. The variations in performance associated with different cold mass assemblers and superconducting cable origins will be discussed.
WEPLS101	First Computation of Parasitic Fields in LHC Dipole Magnet Interconnects	2613
	A. Devred, B. Auchmann, Y. Boncompagni, V. Ferapontov, J.-P. Koutchouk, S. Russenschuck, T. Sahner, C. Vollinger CERN, Geneva
	The Large Hadron Collider (LHC), now under construction at CERN, will rely on about 1600 main superconducting dipole and quadrupole magnets and over 7400 superconducting corrector magnets distributed around the eight sectors of the machine. Each type of magnets is powered by dedicated superconducting busbars running along each sector and passing through the iron yokes of the main dipole and quadruple magnets. In the numerous magnet interconnects, the busbars are not magnetically shielded from the beam pipes and produce parasitic fields that can affect beam optics. We review the 3D models which have been built with the ROXIE software package to evaluate these parasitic fields and we discuss the computation results and their potential impacts on machine performance.
WEPLS102	The Construction of the Superconducting Matching Quadrupoles for the LHC Insertions	2616
	R. Ostojic, P. Canard, N. Catalan-Lasheras, G. Kirby, J.C. Perez, H. Prin, W. Venturini Delsolaro CERN, Geneva
	After several years of intensive effort, the construction of the superconducting matching quadrupoles for the LHC insertions is nearing completion. We retrace the main events of the project from the initial development of quadrupole magnets of several types to the series production of over 100 complex cryo-magnets, and report on the techniques developed for steering of the production. The main performance parameters for the full series, such as quench training, field quality and magnet geometry are presented. The experience gained in the production of these special superconducting magnets is of considerable value for further development of the LHC insertions.
WEPLS103	The Field Description Model for the LHC Quadrupole Superconducting Magnets	2619
	N.J. Sammut, L. Bottura, S. Sanfilippo CERN, Geneva J. Micallef University of Malta, Faculty of Engineering, Msida
	The LHC control system requires an accurate forecast of the magnetic field and the multipole field errors to reduce the burden on the beam-based feed-back. The Field Description for the LHC (FIDEL) is the core of this forecast system and is based on the identification and physical decomposition of the effects that contribute to the total field in the magnet apertures. The effects are quantified using the data obtained from series magnetic measurements at CERN and they are consequently modelled empirically or theoretically depending on the complexity of the physical phenomena. This paper presents a description of the methodology used to model the field of the LHC magnets particularly focusing on the results obtained for the LHC Quadrupoles (MQ, MQM and MQY).
WEPLS104	The Dependence of the Field Decay on the Powering History of the LHC Superconducting Dipole Magnets	2622
	N.J. Sammut, L. Bottura, S. Sanfilippo CERN, Geneva J. Micallef University of Malta, Faculty of Engineering, Msida
	The decay amplitude of the allowed multipoles in the LHC dipoles is expected to perturb the beam stability during the injection phase and is strongly dependent on the powering history of the magnet. The effect is particularly large for the pre-cycle nominal flat-top current and duration. With possible prospects of having different genres of cycles during the LHC operation, the powering history effect must be taken into account in the Field Description Model for the LHC (FIDEL) and must hence be corrected for during machine operation. This paper presents the results of the modelling of this phenomenon. We also discuss the statistic of magnetic measurements required to guarantee that the current history effect is predicted within the specified accuracy.
WEPLS105	Performance of the LHC Arc Superconducting Quadrupoles towards the End of their Series Fabrication	2625
	T. Tortschanoff, P. Hagen, M. Modena, L. Rossi, S. Sanfilippo, K. M. Schirm, E. Todesco, E.Y. Wildner CERN, Geneva R. Burgmer, H.-U. Klein, D. Krischel, B. Schellong, P. Schmidt ACCEL, Bergisch Gladbach M. Durante, A. Payn, F. Simon CEA, Gif-sur-Yvette
	The fabrication of the 408 main arc quadrupole magnets and their cold masses will come to an end in summer 2006. A rich collection of measurement and test data has been accumulated and their analysis is presented in this paper. These data cover the fabrication and the efficiency in the use of the main components, the geometrical measurements and the achieved dimensional precision, the warm magnetic measurements in the factory and the performance at cold conditions, especially the training behaviour. The scrap rate of the NbTi/Cu conductor as well as that of other components turned out to be acceptably low and the quench performance measured was in general very good. Most quadrupoles measured so far exceeded the operating field gradient with one or no quench. The multipole content at cold was measured for a limited numbers of quadrupoles as far as needed for verifying the warm-to-cold correlation. From the point of view of field quality, all quadrupoles could be accepted for the machine and the measures taken to overcome the problem of a too high permeability of a batch of collars are discussed.
WEPLS106	Design, Performance and Series Production of Superconducting Trim Quadrupoles for the Large Hadron Collider	2628
	M. Karppinen, C. Boyer, J.-M. Castro, H.A. Garcia de Sousa Lopes, C. Giloux, J. Mazet, G. Mugnai, V. Remondino, D. Rodrigues, W. Venturini Delsolaro, R. Wolf CERN, Geneva G. Gaggero, L. Loche, M. Tassisto ANSALDO Energia, Magnet & Special Product Division, Genova P. Khare, A. Puntambekar RRCAT, Indore (M.P.)
	The Large Hadron Collider (LHC) will be equipped with several thousands of superconducting corrector magnets. Among the largest ones are the superconducting trim quadrupoles (MQTL). These twin-aperture magnets with a total mass of up to 1700 kg have a nominal gradient of 129 T/m at 1.9 K and a magnetic length of 1.3 m. Sixty MQTL are required for the LHC, 36 operating at 1.9 K in and 24 operating at 4.5 K. The paper describes the design features, and reports the measured quench performance and magnetic field quality of the production magnets. The MQTL magnet production is shared between CERN and industry. This sharing is simplified due to the modular construction, common to all twin-aperture correctors.
WEPLS107	Comparative Study of Inter-strand Coupling Current Models for Accelerator Magnets	2631
	R. de Maria, B. Auchmann, S. Russenschuck CERN, Geneva
	"Inter-Strand Coupling Currents" (ISCCs) contribute to field errors and losses in Rutherford-type superconducting cables in the time^- transient regime. The field change induces eddy currents in loops formed by the superconducting twisted strands and the resistive matrix. In the ROXIE program two models are implemented to simulate ISCCs in a magnet cross-section: A network model uses an electric circuit to represent the geometry of the twisted strands and their resistive contacts; an analytical model simplifies the network equations to determine an equivalent cable magnetization from an average field sweep over the cable. The implementation of the models in ROXIE allows to combine them with models for "Persistent Currents" and "Inter-Filament Coupling Currents". The non-linear iron yoke can be taken into account as well. The predictions of different ISCC models with regard to losses and field errors are compared for two design versions of the LHC main dipole. We find that as far as field quality is concerned, the models perform equally well. As for losses, however, the analytical model cannot capture the complexity of the problem and computes lower losses than the network model.
WEPLS108	High Field Solenoid Magnets for Muon Cooling	2634
	S.A. Kahn, M. Alsharo'a, P.M. Hanlet, R.P. Johnson, M. Kuchnir, D.J. Newsham Muons, Inc, Batavia R.C. Gupta, R. Palmer, E. Willen BNL, Upton, Long Island, New York
	Magnets made with high-temperature superconducting (HTS) coils operating at low temperatures have the potential to produce extremely high fields for use in beam lines and accelerators. The specific application of interest that we are proposing is to use a very high field (of the order of 50 Tesla) solenoid to provide a very small beta region for the final stages of cooling for a muon collider. With the commercial availability of HTS tape based on BSCCO technology with high current carrying capacity at 4.2 K, very high field solenoid magnets should be possible. In this paper we will evaluate the technical issues associated with building this magnet. In particular we will address how to mitigate the high Lorentz stresses associated with this high field magnet.
WEPLS109	Test Results of Fermilab-built Quadrupoles for the LHC Interaction Regions	2637
	M.J. Lamm, R. Bossert, J. DiMarco, SF. Feher, A. Hocker, J.S. Kerby, A. Nobrega, I. Novitski, R. Rabehl, P. Schlabach, J. Strait, C. Sylvester, M. Tartaglia, J. Tompkins, G. Velev, A.V. Zlobin Fermilab, Batavia, Illinois
	The US-LHC Accelerator Project has recently completed the manufacturing and testing of the Q2 optical elements for the LHC interaction region final focus. Each Q2 element consists of two identical quadrupoles (MQXB) with a dipole orbit corrector (MQXB). The Fermilab designed MQXB has a 70 mm aperture and a peak operating gradient of 215 T/m. This paper summarizes the test results for the MQXB program with emphasis on quench performance and alignment studies.
WEPLS110	New Measurements of Sextupole Field Decay and Snapback Effect on Tevatron Dipole Magnets	2640
	G. Velev, P. Bauer, R.H. Carcagno, J. DiMarco, M.J. Lamm, D.F. Orris, P. Schlabach, C. Sylvester, M. Tartaglia, J. Tompkins Fermilab, Batavia, Illinois
	To perform detailed studies of the dynamic effects in superconducting accelerator magnets, a fast continuous harmonics measurement system based on the application of a digital signal processor (DSP) has been built at Fermilab. Using this new system the dynamic effects in the sextupole field, such as the field decay during the dwell at injection and the rapid subsequent "snapback" during the first few seconds of the energy ramp, are evaluated for more than ten Tevatron dipoles from the spares pool. The results confirm the previously observed fast drift in the first several seconds of the sextupole decay and provided additional information on a scaling law for predicting snapback duration. The presented information can be used for an optimization of the Tevatron and for future LHC operations.
WEPLS112	Study of 2-in-1 Large-aperture Nb3Sn IR Quadrupoles for the LHC Luminosity Upgrade	2643
	A.V. Zlobin, V. Kashikhin Fermilab, Batavia, Illinois
	After LHC operates for several years at nominal parameters, it will be necessary to upgrade it to higher luminosity. Replacement of the low-beta insertions with higher performance design based on advanced superconducting magnets is one of the most straightforward steps in this direction. An interesting option for a new IR design is a double bore inner triplet with separation dipoles placed in front of the focusing quadrupoles. This approach reduces the number of parasitic collisions by more than a factor of three with respect to the quadrupoles-first option and allows independent field error correction for each beam. Several designs of the 2-in-1 Nb3Sn quadrupole magnets suitable for the LHC IR upgrade have been studied, including magnets with "cold" and "warm" iron yokes based on symmetric or asymmetric coils. This paper describes the design concepts of 2-in-1 large-aperture IR quadrupoles and compares their major performance parameters, including aperture, field gradient, field quality, electromagnetic stresses in the coils, and discuss some technological aspects of magnet fabrication.
WEPLS114	Progress on the MICE Tracker Solenoid	2646
	M.A. Green, S.P. Virostek LBNL, Berkeley, California W. Lau, S.Q. Yang OXFORDphysics, Oxford, Oxon
	This report describes the 400 mm warm bore tracker solenoid for the Muon Ionization Cooling Experiment (MICE). The 2.923 m long tracker solenoid module includes the radiation shutter between the end absorber focus coil modules and the tracker as well as the 2.780 meter long magnet cryostat vacuum vessel. The 2.554 m long tracker solenoid consists of two sections, a three-coil spectrometer magnet and a two-coil matching section that matches the uniform field 4 T spectrometer solenoid into the MICE cooling channel. The two tracker magnets are used to provide a uniform magnetic field for the fiber detectors that are used to measure the muon beam emittance at the two ends of the cooling channel. This paper describes the design for the tracker magnet coils and the 4.2 K cryogenic coolers that are used to cool the superconducting magnet. Interfaces between the magnet and the detectors are discussed.