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multipole

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WEPCH010 Beam-based Alignment for the Storage Ring Multipoles of Synchrotron SOLEIL quadrupole, alignment, sextupole, SOLEIL 1939
 
  • A. Madur, P. Brunelle, A. Nadji, L.S. Nadolski
    SOLEIL, Gif-sur-Yvette
  First beam-based alignment (BBA) measurements will be carried out during the commissioning of the SOLEIL Storage Ring that will start in April 2006. The results will allow calibrating the zero reading of the 120 Beam Position Monitors (BPMs) with respect to the magnetic centre of the adjacent quadrupoles or sextupoles. BPMs being either adjacent to quadrupoles or sextupoles, we plan to resort to two different BBA methods related to each multipolar magnet. Moreover, as some BPMs are located near both quadrupole and sextupole, the use of both methods will allow us to cross-check the results. We will present here the first results and the comparison with the positions of the magnetic centres as obtained from the magnetic measurements.  
 
WEPCH022 Study of the Effect of Multipolar Components in the SPARC Emittance Compensation Gun Solenoid emittance, quadrupole, gun, cathode 1969
 
  • C. Ronsivalle, G. Dattoli, L. Picardi, M. Quattromini
    ENEA C.R. Frascati, Frascati (Roma)
  • G. Bazzano
    CNAO Foundation, Milan
  • M. Ferrario, M. Migliorati, L. Palumbo, M.A. Preger, C. Sanelli
    INFN/LNF, Frascati (Roma)
  • P. Musumeci
    INFN-Roma, Roma
  • J.B. Rosenzweig
    UCLA, Los Angeles, California
  The SPARC photoinjector rf gun requires a solenoid immediately downstream for emittance compensation. The analysis of the measured solenoid magnetic maps shows the existence of multipolar components added to the pure solenoid field. The effect of these added fields on beam dynamics and possible correction schemes have been studied from the theoretical point of view and by numerical calculations based on PARMELA/TREDI codes. An accurate 3D numerical modelization by using CST EM Studio has been done, in order to investigate the source of these multipolar components and to suggest some design modifications aimed to reduce their magnitude. The results of this study are presented here.  
 
WEPCH072 The High Order Non-linear Beam Dynamics in High Energy Storage Ring of FAIR resonance, sextupole, lattice, octupole 2083
 
  • A.N. Chechenin, R. Maier, Y. Senichev, E. Senicheva
    FZJ, Jülich
  The High Energy Storage Ring (HESR) is part of the international project FAIR for antiproton physics with beam in the momentum range from 1.5 to 15 GeV/c to explore the research areas of hadron structure and quark-gluon dynamics. An important feature of the project is the combination of phase space cooled beams with thick internal targets. Therefore there are two obvious reasons of beam heating: the target-beam interaction and the intra-beam scattering. Another source of the beam size growth is the higher order resonances. In the paper we investigate the non-linear beam dynamics together with different correction schemes minimizing this effect and compare with other sources of beam heating. Since the tune working point has a spread dependent on the chromaticity correction scheme and space charge, we include in our consideration both effects as well. All beam dynamics calculations are carried out with the SIMBAD code from the Unified Accelerator Library (UAL). We use 10000 macro particles, grid sizes 64x64 and 1000 turns per run.  
 
WEPCH088 High Order Aberration Correction controls, simulation, background, quadrupole 2125
 
  • S.N. Andrianov
    St. Petersburg State University, Applied Mathematics & Control Processes Faculty, St. Petersburg
  • A.N. Chechenin
    FZJ, Jülich
  It is known that modern accelerators fall under nonlinear aberrations influence. The most of these aberrations have harmful character, and their effect must be maximally decreased. There are a set of approaches and codes to solving this problem. In this paper, we consider an approach for solving this problem using the matrix formalism for Lie algebraic tools. This formalism allows reducing the starting problem to linear algebraic equations for aberration coefficients, which are elements of corresponding matrices. There are discussed results evaluated using suggested approach and nonlinear programming tools. Some examples of corresponding results are given.  
 
WEPCH102 Studies of the Nonlinear Dynamics Effects of APPLE-II Type EPUs at the ALS polarization, dynamic-aperture, lattice, simulation 2152
 
  • C. Steier, S. Marks, S. Prestemon, D. Robin, D. Schlueter, W. Wan, W. Wittmer
    LBNL, Berkeley, California
  Elliptically Polarizing Undulators (EPUs) have become more and more popular at synchrotron radiation sources, providing full polarization control of the photon beam. The fields of the most commonly used APPLE-II type EPUs have a very fast, intrinsic field roll-off, creating significant non-linearities of the beam motion with in some cases large impact on the dynamic (momentum) aperture. In general, the nonlinear effects get stronger with longer periods and higher undulator magnetic fields. One of the planned future beamlines at the ALS (MERLIN) will use a quasiperiodic EPU with 9 cm period and maximum B fields of about 1.3 T. We will present simulation studies for the proposed shimming schemes for this future device to reduce the nonlinear effects to acceptable values, as well as experimental studies for the existing 5 cm period EPUs already installed in the ALS.  
 
WEPCH112 Database Extension for the Beam Dynamics Simulation Tool V-code quadrupole, simulation, gun, electron 2176
 
  • W. Ackermann, W.F.O. Müller, B. Steiner, T. Weiland
    TEMF, Darmstadt
  • J. Enders, H.-D. Gräf, A. Richter
    TU Darmstadt, Darmstadt
  The beam dynamics simulation tool V-Code has been proved to be very useful in redesigning the injector layout at the superconducting linear accelerator in Darmstadt (S-DALINAC). Modifications in the beam optics are necessary because a new source of polarized electrons should be installed in addition to the existing thermionic gun. The calculations are performed with V-Code which is designed to handle a large amount of individual beam line elements and can therefore be used for extensive accelerator studies. The available database includes all the necessary components like solenoids, quadrupoles and rf cavities, but as a result of their consecutive treatment overlapping external fields are not allowed. Due to geometrical restrictions in the assembly of the new source a space-saving candidate of a quadrupole triplet violates this software-related condition if it is regarded as three distinct quadrupoles. Consequently, a more general beam line element has to be created which treats the lenses as a single unit without interference of their fields to attached cells. The indispensable data base extension together with simulation results and implementation verifications will be presented.  
 
WEPCH150 The Accelerator Markup Language and the Universal Accelerator Parser lattice, quadrupole, collider, CERN 2278
 
  • D. Sagan, M. Forster
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • D.A. Bates, A. Wolski
    LBNL, Berkeley, California
  • T. Larrieu, Y. Roblin
    Jefferson Lab, Newport News, Virginia
  • T.A. Pelaia
    ORNL, Oak Ridge, Tennessee
  • S. Reiche
    UCLA, Los Angeles, California
  • F. Schmidt
    CERN, Geneva
  • P. Tenenbaum, M. Woodley
    SLAC, Menlo Park, California
  • N.J. Walker
    DESY, Hamburg
  A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format.  
 
WEPCH155 Tune-stabilized Linear-field FFAG for Carbon Therapy acceleration, extraction, injection, focusing 2290
 
  • C. Johnstone
    Fermilab, Batavia, Illinois
  • S.R. Koscielniak
    TRIUMF, Vancouver
  The simplicity, smaller aperture, and reduced ring size associated with linear-field, nonscaling FFAGs have made them attractive to investigate for a broad range of applications. Significant progress has recently been made towards understanding and modeling this new type of accelerator. The merits, drawbacks and challenges of the linear-field FFAG are discussed here, in particular its suitability for proton and carbon cancer therapy as compared with conventional synchrotrons and cyclotrons. Specifically, tune stabilization and dynamic aperture, a problem with both scaling and non-scaling FFAGs, will be addressed in detail.  
 
WEPLS072 Results of Field Measurements for J-PARC Main Ring Magnets quadrupole, sextupole, optics, injection 2547
 
  • K. Niki, K. Ishii, Y. Nemoto, E. Yanaoka
    KEK, Ibaraki
  • M. Muto
    New Affiliation Request Pending, -TBS-
  The mass production of J-PARC main ring magnets had been completed till the end of fiscal year 2004. Those magnets consists of 97 bending magnets with 6-m in length, 216 quadrupole magnets with 11 families and 72 sextupole magnets. We have been measured the magnetic field for all of these magnets and we will finish it in March, 2006. The obtained distributions for the BL products of bending magnets and the GL products of quadrupole magnets are within the required tolerance limits, values of which are estimated by the beam optics for COD correction, etc. The measured multi-pole components for these magnets, and so on, will be also reported.  
 
WEPLS080 Magnets for the Storage Ring ALBA quadrupole, sextupole, dipole, storage-ring 2562
 
  • M. Pont
    ALBA, Bellaterra
  • E. Boter, M.L. Lopes
    CELLS, Bellaterra (Cerdanyola del Vallès)
  The Storage Ring ALBA is a 3.0 GeV synchrotron light source under construction in Barcelona (Spain). The Storage Ring, has a circumference of 268.8 m and comprises 32 combined magnets, 112 quadrupoles, and 120 sextupoles. This paper will describe the design and the present state of these magnets. The combined magnet has a central field of 1.42 T and a large gradient of 5.65 T/m, since most of the vertical focusing happens at these combined magnets. The 112 quadrupoles have been designed for a maximum gradient of 22 T/m. The bore diameter will be 61 mm and the lengths range from 200 to 500 mm. Each quadrupole will be individually powered. The 120 sextupoles are divided in 9 families. There are two lengths of sextupoles 150 and 220 mm and the maximum sextupole gradient is 600 T/m2. The bore diameter is 76 mm. The sextupole magnets will also be equipped with additional coils for vertical steering, horizontal steering and quadrupolar skew correction.  
 
WEPLS093 3D Field Computation for the Main Prototype Magnets of the SIS100 Accelerator of the FAIR Project dipole, quadrupole, magnet-design, GSI 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.  
 
WEPLS097 Random Errors in Superconducting Dipoles LHC, dipole, RHIC, simulation 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.  
 
WEPLS101 First Computation of Parasitic Fields in LHC Dipole Magnet Interconnects dipole, LHC, CERN, quadrupole 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.  
 
THPCH008 The Non-linear Space Charge Field Compensation of the Electron Beam in the High Energy Storage Ring of FAIR electron, antiproton, space-charge, resonance 2802
 
  • A.N. Chechenin, R. Maier, Y. Senichev
    FZJ, Jülich
  In the High Energy Storage Ring, a part of the FAIR project at GSI in Darmstadt, the internal target is used. To compensate the interaction of the beam with the target, the electron beam cooling is needed. However, together with the cooling, the non-linear space charge field of electron beam modifies the dynamic aperture. We investigate the possible schemes of this effect compensation using the multi-pole correctors on the HESR.  
 
THPLS026 Front Ends at Diamond undulator, radiation, wiggler, storage-ring 3335
 
  • J. Strachan, D.G. Clarke
    CCLRC/DL, Daresbury, Warrington, Cheshire
  • H.C. Huang, J. Kay
    Diamond, Oxfordshire
  This paper describes the three different types of Front End that have been designed to transmit the intense synchrotron radiation generated by the undulator, multi-pole wiggler and bending magnet sources in the Diamond storage ring to the experiments. The functions of the main components and their location in the layout are described. The Finite Element Analysis that has been carried out to verify the performance under the high heat loads generated by Diamond is also described along with the limits on temperature and stress that have been employed in the design.  
 
THPLS054 Closed Orbit Correction and Beam Dynamics Issues at ALBA lattice, quadrupole, dynamic-aperture, vacuum 3404
 
  • M. Muñoz, D. Einfeld, T.F. Günzel
    ALBA, Bellaterra
  ALBA is a 3 GeV light source being built in Spain. The light source should be operational in 2010.The lattice for the storage ring is now finalized. The basic cells is an extended DBA-like structure with finite dispersion in the straight sections, providing low emittance (under 5nmrad) , small beam cross sections at the source points (less than 150 micro-m horizontal and 10micro-m vertical), and a large number of straight sections (4 times 8m, 12 times 4.2m and 8 times 2.6m). In this paper we review the properties of the lattice with special emphasis in the closed orbit correction system and the lifetime limits.  
 
THPLS120 Tracking Simulations and Dynamic Multipole Shimming for Helical Undulators simulation, undulator, insertion, insertion-device 3562
 
  • G. Wuestefeld, J. Bahrdt, M. Scheer
    BESSY GmbH, Berlin
  Symplectic and fast tracking simulations of an APPLE type undulator for the BESSY II storage ring are presented. The simulation is based on a multiple harmonic decomposition of the magnetic field and on a generating function approach. Because of the relatively large undulator period length of 112 mm, corrections of the dynamic multipoles are required to achieve a good dynamical aperture.  
 
THPLS127 Plans for a 2nd Insertion Device in CAMD wiggler, lattice, TESLA, quadrupole 3583
 
  • V.P. Suller
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • M.G. Fedurin, P. Jines, D.J. Launey, T.A. Miller, Y. Wang
    LSU/CAMD, Baton Rouge, Louisiana
  To allow the possible installation of a 2nd Insertion Device in the CAMD Light Source the lattice optic needs to be changed. The present configuration has a small vertical beta function in the long straight containing the 7T wiggler. The new optic will give small vertical beta at two long straights which are diametrically opposite. Test results with the new optic are presented together with the measured beam parameters. These are used to predict the photon beam performance for several types of Insertion Device which could be installed.  
 
THPLS136 Magnetic Field Multipole Measurement with Hall Probe undulator, insertion-device, insertion, simulation 3604
 
  • Z. Martí
    LLS, Bellaterra (Cerdanyola del Vallès)
  • J. Campmany
    ALBA, Bellaterra
  When assembling an insertion device before shimming, sorting algorithms are used to reduce the field errors by choosing the best arrangement of magnetic blocks. In order to carry it out, magnets to be placed in the array are measured with the Helmholtz coil. This yields the magnetic dipolar moment of each one. In fact, Helmholtz coil measurements assume a dipolar filed for each block. The development of narrow gap insertion devices yields a growing interest in the effect of magnetic inhomogeneities. Magnetic inhomogeneities introduce multipolar terms that are added to those corresponding to the multipole development of an ideal magnetic source. However, magnetic inhomogeneities are not measured so far with the Helmholtz coil, because it evaluates the magnetic field far from the magnet, and the multipolar terms decay faster than the dipolar with distance. In order to take into account inhomogeneities, a new approach could be used, based on the measurement of multipoles corresponding to each block. In this paper we propose a method for the fast measurement of the multipoles corresponding to an arbitrary magnetic block, using a Hall probe scanning along a single straight line.