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sextupole

  
Paper Title Other Keywords Page
MOPKF047 Suppression of Stored Beam Oscillation Excited by Beam Injection injection, storage-ring, synchrotron, optics 414
 
  • T. Ohshima, N. Kumagai, M. Masaki, S. Matsui, H. Ohkuma, K. Soutome, M. Takao, H. Tanaka
    JASRI/SPring-8, Hyogo
  Top-up operation is scheduled from May 2004 at SPring-8. For this operation it is important that frequent beam injections should not excite the oscillation of stored beams. However, injection bump orbit was not closed perfectly and residual beam oscillations lead to increase of effective beam sizes by twice and three times in the horizontal and vertical direction respectively. We are trying to reduce these excited oscillations to less than one third of the usual beam sizes. For the suppression of horizontal one, we applied a novel scheme to reduce the effect due to the nonlinearity of sextupole magnets by adjusting the strength ratio of the sextupoles. The field similarity of bump magnets was also improved by replacing them with newly designed ones, where the effect of eddy current at the end plates was reduced. These countermeasures suppressed the horizontal oscillation by about one order. For the suppression of vertical one, the excitation mechanism has being investigated in detail. Presently the tilt angle adjustment of bump magnets reduced the vertical oscillation by one third. For further reduction of these oscillations, corrections with pulse-magnets is under investigation.  
 
MOPKF062 Choice of Arc Design for the ERL Prototype at Daresbury Laboratory dipole, quadrupole, linac, beam-transport 452
 
  • H.L. Owen, B.D. Muratori
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  The choice of arc design for the Energy Recovery Linac Prototype (ERLP) to be built at Daresbury Laboratory is investigated. Both the overall merits and disadvantages of a TBA arc and Bates bend are considered, and space restrictions particular to Daresbury Laboratory given. Some magnet parameters are given together with a summary of the layout of the ERLP.  
 
MOPKF073 Design Study of the Bending Sections between Harmonic Cascade FEL Stages dipole, quadrupole, electron, simulation 485
 
  • W. Wan, J.N. Corlett, W. Fawley, A. Zholents
    LBNL, Berkeley, California
  The present design of LUX (linac based ultra-fast X-ray facility) includes a harmonic cascade FEL chain to generate coherent EUV and soft X-ray radiation. Four cascade stages, each consisting of two undulators acting as a modulator and a radiator, respectively, are envisioned to produce photons of approximate wavelengths 48 nm, 12 nm, 4 nm and 1 nm. Bending sections may be placed between the modulator and the radiator of each stage to adjust and maintain bunching of the electrons, to separate, in space, photons of different wavelengths and to optimize the use of real estate. In this note, the conceptual design of such a bending section, which may be used at all four stages, is presented. Preliminary tracking results show that it is possible to maintain bunch structure of nm length scale in the presence of errors, provided that there is adequate orbit correction and there are 2 families of trim quads and trim skew quads, respectively, in each bending section.  
 
MOPLT014 Testing of the LHC Magnets in Cryogenic Conditions: Current Experience and Near Future Outlook dipole, multipole, injection, instrumentation 560
 
  • V. Chohan, M. Buzio, G. De Rijk, J. Miles, P. Pugnat, V. Remondino, S. Sanfilippo, A.D. Siemko, N. Smirnov, B. Vullierme, L. Walckiers
    CERN, Geneva
  For the Large Hadron Collider under construction at CERN, a necessary and primordial condition prior to its installation is that all the main twin-aperture Dipole and Quadrupole magnets are tested in the 1.9K cryogenic conditions. These tests are not feasible at the manufacturers and hence, are carried out at CERN at a purpose built facility on the site. This presentation will give an overall view of the issues related to the operation of the tests facility. In particular, it will give the goals that need to be met to ensure the magnet integrity and performance and the context & constraints on the test programme. Results accumulated from the tested magnets and the ensuing tests stream-lining will be presented, together with some of the explanations and hard limits. Finally, some improvements planned for efficient operation will be given within the confines of the testing programme as was foreseen and the project goals and deadlines.  
 
MOPLT024 Flexibility, Tolerances, and Beam-Based Tuning of the CLIC Damping Ring coupling, betatron, damping, closed-orbit 590
 
  • M. Korostelev, J. Wenninger, F. Zimmermann
    CERN, Geneva
  The present design of the CLIC damping ring can easily accommodate anticipated CLIC parameter changes. Realistic misalignments of magnets and monitors increase the equilibrium emittance. In simulations we study both the sensitivity to magnet displacements and the emittance recovery achieved by orbit correction, dispersion-free steering and coupling compensation.  
 
MOPLT046 Overcoming Performance Limitations due to Synchrobetatron Resonances in the HERA Electron Ring resonance, optics, closed-orbit, betatron 650
 
  • F.J. Willeke
    DESY, Hamburg
  The HERA Electron Ring was suffering from strong synchrobetatron resonances which have been particularly detrimental after the HERA luminosity upgrade because of a reduced sychrotron tune due to stronger transverse focusing and a shift in the damping distribution in favor of transverse damping. It turned out to be most difficult to store a beam at the preferred working point for high electron spin polarization between the 2nd and the 3rd synchro-betatron satellite of the horizontal integer resonance. A comparative study of the resonance strength did not reveal any significant additional disadvantage of the new beam optics. However, a mechanism driven by closed orbit distortions was discovered which can increase the width of the resonance Qx+2Qs=0 by a large factor. This explains the operational difficulties. The remedy against this effect is quite straight forward. The Fourier component of the closed orbit near the horizontal tune must be avoided. This is enforced in HERA operations by rigerous orbit corrections and an orbit feedback system which reproduces well-corrected orbits reliably. Synchrobetatron resonances do not constitute a performance limitation of polarized lepton proton collisions in HERA any more.  
 
MOPLT047 Lattice Design Study for HESR quadrupole, lattice, target, focusing 653
 
  • Y. Senichev, S. An, K. Bongardt, R. Eichhorn, A. Lehrach, R. Maier, S. Martin, D. Prasuhn, H. Stockhorst, R. Tölle
    FZJ/IKP, Jülich
  The important feature of High Energy Storage Ring is the combination of phase space cooled beams with internal targets, which allows to reach high luminosities up to 2*1032cm-2s-1. However, the requirement to have the strongly focused beam on the target causes the high chromaticity value on the target straight section and as in result to the squeezing of dynamic aperture after sextupole correction of the chromaticity. Simultaneously, the momentum-compaction factor is one of the most important characteristics of an accelerator, which defines the collective instability threshold. Therefore, the HESR lattice has to have the following features: low or negative momentum compaction factor, dispersion free straight sections, convenient method to correct the chromaticity by the sextupoles, sufficiently large dynamic aperture. In this work we develop lattice, which meets all these requirements for HESR.  
 
MOPLT120 Proposals for Improvements of the Correction of Sextupole Dynamic Effects in the Tevatron Dipole Magnets injection, dipole, luminosity, collider 818
 
  • P. Bauer, G. Ambrosio, J. Annala, J. DiMarco, R. Hanft, M. Lamm, M. Martens, P. Schlabach, D. Still, M. Tartaglia, J. Tompkins, G. Velev
    Fermilab, Batavia, Illinois
  It is well known that the sextupole (b2) components in the superconducting dipole magnets decay during the injection plateau and snap back rapidly at the start of the ramp to flat top current. These so-called dynamic effects were originally discovered in the Tevatron. They are compensated for by the chromaticity correctors distributed around the ring. Imperfect control of the chromaticity during the snapback can contribute to beam loss and emittance growth. A thorough investigation of the chromaticity correction in the Tevatron was launched in the context of Run II, including beam chromaticity measurements and extensive magnetic measurements on a series of spare Tevatron dipole magnets. The study has yielded new information about the effect of the powering history on the dynamic b2. A companion paper at this conference describes in detail the results of these magnetic measurements [reference to George Velev's paper]. Study findings have given directive to new proposals for improvement of the b2 snapback correction in the Tevatron, including a revised functional form for the snapback algorithm and the elimination of the beam-less pre-cycle. This paper reports the results of beam studies performed recently to test these improved procedures.  
 
MOPLT128 Lattice Effects due to High Currents in PEP-II luminosity, emittance, synchrotron, photon 836
 
  • F.-J. Decker, H. Smith, J.L. Turner
    SLAC, Menlo Park, California
  The very high beam currents in the PEP-II B-Factory have caused many expected and unexpected effects: Synchrotron light fans move the beam pipe and cause dispersion, higher order modes cause excessive heating, e-clouds around the positron beam blow up its beam size. Here we describe an effect were the measured dispersion of the beam in the Low Energy Ring (LER) is different at high and at low beam currents. The dispersion was iteratively lowered by making anti-symmetric orbit bumps in many sextupole duplets, checking each time with a dispersion measurement where a dispersive kick is generated. This can be done parasitically during collisions. It was a surprise when checking the low current characterization data that there is a change. Subsequent high and low current measurements confirmed the effect. It is located far away from any synchrotron radiation in the middle of a straight (PR12), away from sextupoles and skew quadrupoles and creates a dispersion wave of about 70 mm at high current while at low current it is negligible.  
 
MOPLT139 Beam-based Alignment and Beta Function Measurements in PEP-II quadrupole, closed-orbit, simulation, luminosity 866
 
  • G. Yocky, J. Nelson, M.C. Ross, T.J. Smith, J.L. Turner, M. Woodley
    SLAC, Menlo Park, California
  Careful optics studies and stringent lattice control have been identified as two key components to increasing PEP-II luminosity. An accurate, trusted BPM system is required for both of these strategies. To validate the existing BPM system and to better understand some optical anomalies in the PEP-II rings, an aggressive program of beam-based alignment (BBA) has been initiated. Using a quad-shunt BBA procedure in which a quadrupole?s field strength is varied over a range of beam positions, relative offsets are determined by the BPM readings at which quadrupole field changes no longer induce a closed orbit shift. This procedure was verified in the HER and is well underway in the LER IR. We have found many surprisingly large BPM offsets, some over one centimeter, as well as a number of locations where the current nominal orbit is several millimeters from the quadrupole center. Tune versus quadrupole field data were taken during the BBA process in the LER IR, and the non-linear response in each case is compared to simulation to infer local beta functions.  
 
MOPLT142 Analysis of KEK-ATF Optics and Coupling Using LOCO coupling, quadrupole, emittance, focusing 872
 
  • M. Woodley, J. Nelson, M.C. Ross
    SLAC/NLC, Menlo Park, California
  • A. Wolski
    LBNL/AFR, Berkeley, California
  LOCO is a computer code for analysis of the linear optics in a storage ring based on the closed orbit response to steering magnets. The analysis provides information on focusing errors, BPM gain and rotation errors, and local coupling. Here, we discuss the details of the LOCO implementation at the KEK-ATF Damping Ring, and report the initial results. Some of the information obtained, for example on the BPM gain and coupling errors, has not previously been determined. We discuss the possibility of using the data provided by the LOCO analysis to reduce the vertical emittance of the ATF beam.  
 
TUPLT019 Nonlinear Effects Studies for a Large Acceptance Collector Ring quadrupole, optics, dynamic-aperture, lattice 1177
 
  • A. Dolinskii, K. Beckert, P. Beller, B.  Franzke, F. Nolden, M. Steck
    GSI, Darmstadt
  A large acceptance collector ring (CR) is designed for fast cooling of rare isotope and antiproton beams, which will be used for nuclear physics experiments in the frame of the new international accelerator facility recently proposed at GSI. This contribution describes the linear and non-linear optimisation used to derive a lattice solution with good dynamic behaviour simultaneously meeting the demands for very fast stochastic cooling for two optical modes (for rare isotope and antiproton beams). Effects due to non-linear field contributions of the magnet field in dipoles and quadrupoles are very critical in this ring. Using a single particle dynamics approach, the major magnetic non-linearities of the CR are studied. We discuss the particle dynamics of the dipole and quadrupole fringe fields and the their influence on the dynamic aperture and on the tune. Additionally, the CR will be operated at the transition energy (isochronous mode) for time of flight (TOF) mass spectrometery of short-lived radioactive ions. For this mode a specific correction scheme is required to reach a high degree of isochronism over a large acceptance.  
 
TUPLT036 Optimization of Low Emittance Lattices for PETRA III lattice, wiggler, damping, emittance 1225
 
  • W. Decking, K. Balewski
    DESY, Hamburg
  The reconstruction of the existing 2.3 km long storage ring PETRA II into a 3rd generation synchrotron light source (PETRA III) calls for an horizontal emittance of 1 nm rad. In addition the on- and off-momentum dynamic acceptance should be large to ensure sufficient injection efficiency and beam lifetime. We present three different types of lattices for the arcs of PETRA: a so-called TME lattice and a FODO lattice which both are newly designed to reach the specified emittance and the present FODO lattice with damping wigglers. The different lattice types have been compared through tracking calculations, including wiggler nonlinearities. Only the relaxed FODO lattice with damping wigglers meets the acceptance goals.  
 
TUPLT059 Evolution of Optical Asymmetries in the Elettra Storage Ring quadrupole, betatron, optics, storage-ring 1288
 
  • F. Iazzourene, S. Di Mitri, E. Karantzoulis, L. Tosi
    ELETTRA, Basovizza, Trieste
  Optical asymmetries have been measured and analyzed, before and after the magnet realignments. One way is to compare theoretical to measured orbit response matrices. Another way is to analyze the measured response matrix itself, by comparing the measured effects at identical optical positions. To evaluate the effects of the sextupoles on the optical asymmetries, the measurements have been performed with the sextupoles ON and OFF. The impact of a partial realignment is also analyzed both by varying the quadrupole excitations as well as by performing dispersion and coupling measurements. The results are presented in this paper.  
 
TUPLT076 Optimization of Sextupole Strengths in a Storage Ring for Top-up Operation injection, optics, storage-ring, synchrotron 1330
 
  • H. Tanaka, T. Ohshima, K. Soutome, M. Takao, H. Takebe
    JASRI/SPring-8, Hyogo
  In top-up operation of a light source, electron or positron beams are frequently injected to keep the stored current constant. Closing an injection bump orbit is thus critically important not to disturb precise experiments. However, there are sextupole magnets inside the injection bump in the SPring-8 storage ring and the bump never closes all over the bump amplitude due to the sextupole nonlinearity. To solve the problem, we proposed a scheme based on minimum condition for the injection bump leakage. The scheme only restricts the sextupole strengths within the bump. Introduction of other sextupole families outside the bump can enlarge the dynamic aperture (DA) of the ring with keeping the minimum leakage. To find the best solution, we optimized the sextupole strengths changing the number of sextupole family as a parameter. The simulation shows that addition of two sextupole families sufficiently enlarges DA. Cabling of the sextupole magnets was partly changed in the summer 2003 and the effects of the strength optimization on the bump leakage, injection efficiency and beam lifetime has been investigated experimentally. We present the obtained results compared with the simulations.  
 
TUPLT134 Lattice of NSC KIPT Compact Intense X-ray Generator NESTOR electron, storage-ring, lattice, laser 1440
 
  • A.Y. Zelinsky, P. Gladkikh, I.M. Karnaukhov, V. Markov, A. Mytsykov, A.A. Shcherbakov
    NSC/KIPT, Kharkov
  The new generation of the intense X-rays sources based on low energy electron storage ring and Compton scattering of laser beam allows to produce X-rays with intensity up to 1014 phot/s. One of the main traits of a storage ring lattice for such generator type is using of magnetic elements with combined focusing functions such as bending magnets with quadrupole and sextupole field components. In combination with very low bending radius and dense magnetic elements setting along ring circumference it leads to increasing of 3D magnetic field effects on electron beam dynamics and can decrease generated radiation intensity drastically. For the reasons of very low electron beam size at the interaction point and strong focusing in a compact storage ring the questions of determination of accuracy of bending magnet is very important too. The paper is devoted to the description of lattice of NSC KIPT Compact X-ray generator NESTOR. The results of investigations of the effects of 3D magnetic field and harmonic compound due to manufacture errors of bending magnets, bending magnet and lenses edges on electron beam dynamics are presented.  
 
TUPLT153 Orbit Response Matrix Analysis Applied at PEP-II lattice, coupling, interaction-region, luminosity 1488
 
  • C. Steier, A. Wolski
    LBNL/AFR, Berkeley, California
  • S. Ecklund, J.A. Safranek, P. Tenenbaum, A. Terebilo, J.L. Turner, G. Yocky
    SLAC, Menlo Park, California
  Beam-based techniques to study lattice properties have proven to be a very powerful tool to optimize the performance of storage rings. The analysis of orbit response matrices has been used very successfully to measure and correct the gradient and skew gradient distribution in many accelerators. The first applications were mostly in synchrotron light sources, but the technique is also used increasingly at colliders. It allows determination of an accurately calibrated model of the coupled machine lattice, which then can be used to calculate the corrections necessary to improve coupling, dynamic aperture and ultimately luminosity. At PEP-II, the Matlab version of LOCO has been used to analyze coupled response matrices for both the LER and the HER. The large number of elements in PEP-II and the very complicated interaction region present unique challenges to the data analysis. The orbit response matrix analysis will be presented in detail, as well as results of lattice corrections based on the calibrated machine model.  
 
TUPLT189 Dipole and Quaqdrupole Sorting for the SNS Ring quadrupole, dipole, resonance, multipole 1574
 
  • D. Raparia, A.V. Fedotov, Y.Y. Lee, J. Wei
    BNL, Upton, Long Island, New York
  The Spallation Neutron Source (SNS) accumulator ring is a high intensity ring and must have low uncontrolled losses for hands on maintenance. To achieve these low losses one needs very tight tolerance. These tight tolerances have been achieved through shimming the magnets and sorting. Dipoles are solid core magnets and had very good field quality but magnet to magnet variation were sorted out according to ITF, since all the dipole are powered with one power supply. Typically, sorting is done to minimize linear effects in beam dynamics. Here, sorting of quadrupoles was done according to a scheme which allows to reduce unwanted strength of nonlinear resonances. As a result, the strength of sextupole resonances for our base line tune-box was strongly reduced which was confirmed by a subsequent beam dynamics simulation.  
 
TUPLT191 Transverse Optics Improvements for RHIC Run 4 optics, power-supply, dipole, injection 1580
 
  • J. Van Zeijts
    BNL, Upton, Long Island, New York
  The magnetic settings in RHIC are driven by an online model, and the quality of the resulting lattice functions depend on the correctness of the settings, including knowledge of the magnet transfer-functions. Here we first present the different inputs into the online model, including dipole sextupole compenents, used to set tunes and chromaticities along the ramp. Next, based on an analysis of measured tunes and chromaticities along the fy03 polarized proton ramp, we present predictions for quadrupole transfer-function changes. The changes are implemented for the fy04 Au ramp, and we show the improved model agreement for tunes, and chromaticities along the ramp, and measured transverse phase-advance at store. We also describe model improvements for derived observables like the quality of transverse bump closure and observed luminosity ratios between individual interaction points.  
 
WEXCH01 Experience with LHC Magnets from Prototyping to Large-scale Industrial Production and Integration dipole, target, quadrupole, superconducting-magnet 118
 
  • L. Rossi
    CERN, Geneva
  The construction of the LHC superconducting magnets is approaching one third of its completion. At the end of 2003, main dipoles cold masses for more than one octant were delivered; meanwhile the winding for the second octant was almost completed. The other big magnets, like the main quadrupoles and the insertion quadrupoles, have entered into series production as well. Providing more than 20 km of superconducting magnets, with the quality required for an accelerator like LHC, is an unprecedented challenge in term of complexity that has required several steps from the construction of 1 meter-long magnets in the laboratory to today production of more than one 15 meter-long magnet per day in Industry. The work and its organization is made even more complex by the fact that CERN supplies most of the critical components and part of the main tooling to the magnet manufacturers, both for cost reduction and for quality issues. In this paper the critical aspects of the construction and the time plan will be reviewed and the actual achievements in term of quality and construction time will be compared with the expectations.  
Video of talk
Transparencies
 
WEPKF009 A Scaling Law for Predicting Snap-back in Superconducting Accelerator Magnets dipole, injection, multipole, magnet-design 1609
 
  • T. Pieloni, L. Bottura, S. Sanfilippo
    CERN, Geneva
  • G. Ambrosio, P. Bauer
    Fermilab, Batavia, Illinois
  • M. Haverkamp
    METROLAB, Plan-les-Ouates
  The decay of the sextupole component in the bending dipoles during injection and the subsequent snap-back at particle acceleration are issues of common concern, albeit at different levels of criticality, for all superconducting colliders built (Tevatron, HERA, RHIC) or in construction (LHC) to date. The main difficulty is the correction of the relatively large and fast sextupole change during snap-back. Motivated by the above considerations, we have conducted an extended study of sextupole snap-back on two different magnet families, the Tevatron and the LHC bending dipoles, using the same measurement method. We show in this paper that it is possible to generalise all the results obtained by using a simple, exponential scaling law. Furthermore, we show that for magnets of the same family the parameters of the scaling law correlate linearly. This finding could be exploited during accelerator operation to produce accurate forecast of the snap-back correction based solely on beam-based measurements.  
 
WEPKF010 Design of an Automatic System for the Electrical Quality Assurance during the Assembly of the Electrical Circuits of the LHC instrumentation, dipole, quadrupole, superconducting-magnet 1612
 
  • D. Bozzini, V. Chareyre, A. Jacob, K.H. Mess, S. Russenschuck, R. Solaz Cerdan
    CERN, Geneva
  During the assembly of the LHC one of the challenges will be the correct wiring of the 1712 circuits powering the 10094 magnet units, for which all-together 70000 splices have to be done. Considering the complexity of the electrical scheme the risk of wrong wiring is high. Errors, if not detected during the assembly phase, will perturb the LHC operation. A method has been developed to verify automatically the cabling scheme. It first detects the continuity of a portion of circuit and then verifies the correct polarity and type of the magnets in the circuit. A 108-meter LHC cell is the shortest length that can be tested. The system is composed of a unit to be placed at the center of the cell and two de-multiplexers positioned at the extremities of the cell. The central unit contains a data acquisition system where in total 217 signals can be acquired and more than 3000 voltage combinations are possible. Pointing to different databases, a LabVIEW program automatically executes the test procedure, generates, and stores the reports. The hardware and software design, the data flow between databases, and the testing methodology applied to the different circuit types are described.  
 
WEPKF012 LHC Dipole Axis, Spool Piece Alignment and Field Angle in Warm and Cold Conditions dipole, alignment, laser, quadrupole 1618
 
  • M. Coccoli, M. Buzio, J. Garcia Perez
    CERN, Geneva
  The installation and commissioning of the LHC dipoles requires the knowledge of the magnetic axis and of the spool piece corrector alignment at the operating conditions. The installation is based at present on the use of geometric information derived from mechanical measurements performed in warm conditions, with the assumption that the geometric and magnetic axis are coincident. Any discrepancies between mechanical and magnetic axis and unforeseen geometry variations from ambient to cold operating temperature can introuduce important uncertaintes in the prediction of the alignment at operational conditions. Such prediction is studied through correlations between measurements performed at room and liquid helium temperature. A statistic analysis of the measurement data available is presented showing uncertainties on the correctors alignment. They are compared with beam-based specifications of the positioning of the spool piece.  
 
WEPKF022 Electro-mechanical Aspects of the Interconnection of the LHC Superconducting Corrector Magnets quadrupole, dipole, octupole, monitoring 1645
 
  • J.-P.G. Tock, D. Bozzini, F. Laurent, S. Russenschuck, B. Skoczen
    CERN, Geneva
  In addition to the main 1232 bending dipoles and 474 focusing and defocusing quadrupoles, more than 6800 superconducting corrector magnets are included in the LHC machine. They are housed in the superfluid helium enclosures of the main cryomagnets. Among them, the closed orbit correctors (sextupole and octupole) are integrated in the main quadrupole helium vessel and they are powered via an externally routed cryogenic line (line N). During the assembly, these corrector magnets have to be connected according to a complex electrical scheme based on the optical requirements of the LHC machine. Along the 27-km long LHC machine, 440 interconnection boxes are installed and will allow the powering of the correctors by means of a 42-wires auxiliary bus-bar cable, of which the corresponding wires have to be routed to the SSS from the interconnection box. Stringent requirements in terms of volume, mechanical resistance, electrical conductance and insulation, reliability, and respect of the electrical schematics apply during the assembly and splicing of the junctions inside the line-N box. The activities and their sequence, aiming at ensuring the fulfilment of these requirements are presented. The planned activities (assembly, ultrasonic welding, general and electrical inspection, and electrical qualification) and the interactions between the various intervening teams are described.  
 
WEPKF024 The Geometry of the LHC Main Dipole dipole, site 1648
 
  • E.Y. Wildner, J. Beauquis, G. Gubello, M. La China, W. Scandale
    CERN, Geneva
  The 15 m long main dipole of the Large Hadron Collider has a curvature following the beam trajectory with the aim to minimize the necessary coil aperture. To avoid feed-down effects and mechanical aperture restrictions strong constraints have to be imposed on the construction of the magnet in terms of tolerances and stability of the cold mass during transport, cryostating, cold tests and installation in the LHC tunnel. In this paper we show the behaviour of the shape of the magnet using available measurements taken at different stages of construction and assembly. In particular we discuss the evolution of the sagitta and the positioning of the corrector magnets that are used to compensate the multipole field errors. We propose alignment procedures to be used in case magnets are out of tolerance after transport and cold tests. The twist of the magnet and its relation to the field angle will also be discussed.  
 
WEPKF030 The Storage Ring Magnets of the Australian Synchrotron quadrupole, dipole, storage-ring, focusing 1666
 
  • E. Huttel
    FZK-ISS-ANKA, Karlsruhe
  • B. Barg, A. Jackson, G. LeBlanc
    ASP, Melbourne
  • J. Tanabe
    SLAC, Menlo Park, California
  A 3 GeV Synchrotron Radiation Source is being built up in Melbourne, Australia. The storage ring has a circumference of 216 m and has a 14 fold DBA structure. For the storage ring the following magnets are required: 28 gradient dipoles, with B = 1.3 T, B’ = 3.35 T/m, 56 quadrupoles with a gradient of B’ = 18 T/m, 28 quadrupoles with a gradient of 9 T/m, 56 sextupoles with d2B/dr2 = 320 T/m2 and 42 with 150 T/m2. The design of pole faces was done by scaling the SPEAR III pole face to the required gap and bore of the ASP storage ring magnets. The sextupoles will be equipped with coils for horizontal and vertical correction and for a skew quadrupole. The design of the magnets and the calculated magnetic properties will be presented.  
 
WEPKF034 The Modified DAFNE Wigglers wiggler, collider, betatron, octupole 1678
 
  • S. Guiducci, S. Bertolucci, M. Incurvati, M.A. Preger, P. Raimondi, C. Sanelli, F. Sgamma
    INFN/LNF, Frascati (Roma)
  Modifications to the pole shape of a spare wiggler have been tested to increase the width of the good field region, with the aim of reducing the effect of nonlinearities affecting the dynamic aperture and the beam-beam interaction. Additional plates realized with the same material of the pole have been machined in several shapes and glued on the poles. Accurate measurements of the vertical field component on the horizontal symmetry plane of the magnet have been performed to find the best profile. The particle motion inside the measured field has been simulated to minimize the field integral on the trajectory, to determine the wiggler transfer matrix and to estimate the amount of non linear contributions. All wigglers in the collider have been modified to the optimized pole shape. Measurements with beam performed with the modified wigglers show a significant reduction of nonlinearities.  
 
WEPKF075 Measurements of Sextupole Decay and Snapback in Tevatron Dipole Magnets injection, dipole, acceleration, superconductivity 1780
 
  • G. Velev, J. Annala, P. Bauer, J. DiMarco, H. Glass, R. Hanft, R. Kephart, M. Lamm, M. Martens, P. Schlabach, C. Sylvester, M. Tartaglia, J. Tompkins
    Fermilab, Batavia, Illinois
  To optimize the performance of the Fermilab Tevatron accelerator in Collider Run II, we have undertaken a systematic study of the drift and subsequent snapback of dipole magnet harmonics. The study has mostly focused on the dynamic behavior of the normal sextupole component, b2, as measured in a sample of spare Tevatron dipoles at the Fermilab Magnet Test Facility. We measured the dependence of the decay amplitude and the snapback time on Tevatron ramp parameters and magnet operational history. A series of beam studies was also performed [*]. This paper summarizes the magnetic measurement results and describes an optimization of the b2 correction scheme which is derived from these measurements.

* P.Bauer et al. These proceedings.

 
 
WEPKF084 SPEAR3 LARGE DC MAGNET POWER SUPPLIES power-supply, synchrotron, feedback, quadrupole 1801
 
  • A.C. de Lira, P. Bellomo
    SLAC, Menlo Park, California
  The Stanford Synchrotron Radiation Laboratory (SSRL) has successfully commissioned SPEAR3, its newly upgraded 3-GeV synchrotron light source. First stored beam occurred December 15, 2003 and 100mA operation was reached on January 20, 2004. This paper describes the specification, design, and performance of the SPEAR3 DC magnet large power supplies (LGPS) that consist of tightly-regulated (better than 10 ppm) current sources ranging from 100 A to 225 A and output powers ranging from 70kW to 135kW. A total of 6 LGPS are in successful operation and are used to power strings of quadrupoles, and sextupoles. The LGPS are isolated by a delta/delta-wye 60Hz step-down transformer that provide power to 2 series connected chopper stages operating phase-shifted at a 16 kHz switching frequency to provide for fast output response and high efficiency. Also described are outside procurement aspects, installation, in-house testing, and operation of the power supplies.  
 
WEPLT003 The Study of 2D Sextupole Coupling Resonances at VEPP-4M resonance, dynamic-aperture, coupling, betatron 1819
 
  • V.A. Kvardakov, E. Levichev, A.I. Naumenkov, P.A. Piminov
    BINP SB RAS, Novosibirsk
  The Study of 2D Sextupole Coupling Resonances at VEPP-4M  
 
WEPLT039 Measurement and Compensation of Second and Third Order Resonances at the CERN PS Booster resonance, booster, injection, coupling 1918
 
  • P. Urschütz
    CERN, Geneva
  Space charge effects at injection are the most limiting factor for the production of high brightness beams in the CERN PS Booster. The beams for LHC, CNGS and ISOLDE feature incoherent tune spreads exceeding 0.5 at injection energy and thus cover a large area in the tune diagram. Consequently these beams experience the effects of transverse betatron resonances and efficient compensation is required. Several measurements have been performed at the PS Booster in 2003, aiming at a detailed analysis of all relevant second and third order resonances and an optimisation of the compensation scheme. Special attention was paid to the systematic 3Qy=16 resonance. To avoid this particularly dangerous resonance an alternative working point was tested. A comparison of resonance driving terms and compensation settings for both working points was made and important differences in the strengths of the resonances were found. The peculiarities when measuring third order coupling resonance driving terms are also mentioned.  
 
WEPLT050 Frequency Map Measurements at BESSY resonance, storage-ring, lattice, quadrupole 1951
 
  • P. Kuske, O. Dressler
    BESSY GmbH, Berlin
  With two dedicated diagnostic kicker magnets and a turn-by-turn, bunch-by-bunch beam position monitor frequency maps were measured under various operating conditions of the BESSY storage ring. Depending on the number and type of insertion devices in operation additional resonances show up. Details of the experimental setup as well as the data analysis are presented. The results will be compared with theoretical calculations which are based on the linear model of the storage ring lattice extracted from measured response matrices. Non-linear elements are added to the model in order to describe the effect of the strong sextupole magnets, the horizontal corrector magnets installed in these magnets, and of some of the insertion devices.  
 
WEPLT064 2-nd Order Sextupole Effects on the Dynamic Aperture in HERA-e resonance, octupole, luminosity, optics 1993
 
  • M. Vogt
    DESY, Hamburg
  During the first year after the luminosity upgrade HERA-e was operated in a mode for which the accessible area in transverse tune space was determined by resonances driven by sextupoles in 2-nd order. It turned out that with typical total incoherent beam beam tune shifts (.05,.08) for 2 IPs this space was too small for stable operation. We have used 2-nd order canonical perturbation theory to analyze the impact of the increased sextupole strengths in the upgraded lattice on the relevant resonance strengths and the detuning. Moreover, we have studied whether it is possible to compensate the resonances with localized octupole schemes (6 or 9 independent magnets) to 1-st and 2-nd order, computed the resulting detuning and compared the results with 6D tracking.  
 
WEPLT107 Nonlinear field Effects in the JPARC Main Ring resonance, injection, betatron, space-charge 2101
 
  • A.Y. Molodojentsev, S. Machida, Y. Mori
    KEK, Ibaraki
  Main Ring (MR) of the Japanese Particle Accelerator Research Complex (JPARC) should provide acceleration of the high-intensity proton beam from the energy of 3GeV to 50 GeV. The expected beam intensity is 3.3·1014 ppp and the repetition rate is about 0.3 Hz. The imaginary transition lattice of the ring was adopted, which has the natural linear chromaticity about (-30) for both transverse phase planes. The expected momentum spread of the captured particles before the acceleration is less than 0.007. Two independent families of the chromatic sextupole magnets are use to eliminate the linear chromatic tune shift. This chromatic sextupole field nonlinearity will excite the normal 'octupole' resonances and will lead to the amplitude dependent tune shifts in both transverse phase planes. Additional sextupole magnets are planed to excite the third-order horizontal resonance, which will be used for the slow extraction. Incoherent tune shift of the low-energy proton beam is about (-0.16) so that some particles could cross nearest low-order resonances. Optimization of the 'bare' working point of MR at the injection energy has been performed to minimize the influence of the linear coupling and high-order coupling resonances. Excitation of the linear coupling resonance has been introduced by the realistic misalignment errors adopted for MR. The 'bare' working point during the slow extraction has been analyzed. The influence of the normal sextupole resonances on the large amplitude particle behavior at the scraper location has been studied including random sextupole field component of the MR bending magnets. Realistic distortion of the ideal ring super-periodicity by the injection kicker magnets has been included in the tracking procedure for the on- and off-momentum particles. Finally, correction schemes have been considered for most dangerous resonances around the optimized 'bare' working point. The space-charge effects of the proton beam have not been included in this study.  
 
WEPLT136 Lattice Studies For The MAX-IV Storage Rings lattice, dynamic-aperture, closed-orbit, octupole 2155
 
  • H. Tarawneh, M. Eriksson, L.-J. Lindgren, S. Werin
    MAX-lab, Lund
  • B. Anderberg
    AMACC, Uppsala
  • E.J. Wallén
    ESRF, Grenoble
  The lattice for the future MAX-IV storage rings at MAX-Lab has been studied, The MAX IV facility consists of two similar rings operated at 1.5 GeV and 3 GeV electron energies, The ring consists of 12 supercells each built up by 5 unit cells and matching sections. The high periodicity of the lattice combined with the high gradients in the small gap dipole magnets yield a small emittance of 1 nm.rad, good dynamic aperture and momentum acceptance. In the matching section, a soft end dipole magnet is introduced to reduce the synchrotron radiation power hitting the upstream straight section.  
 
THPKF007 Canadian Light Source Status and Commissioning Results quadrupole, injection, storage-ring, dipole 2269
 
  • L. Dallin, R. Berg, J.C. Bergstrom, X. Shen, R.M. Silzer, J.M. Vogt, M.S. de Jong
    CLS, Saskatoon, Saskatchewan
  The storage ring for the Canadian Light Source (CLS) was completed in August 2003. By January 2004, after about shifts of commissioning beam currents of up to 25 mA with 0.7 hr lifetimes were achieved. Injection times for 25 mA are about 4 minutes. Commissioning activities include global orbit correction, measurement of machine parameters and beam-based diagnostices. Features of the CLS are a compact lattice (170 m) for a 2.9 GeV storage ring, high performance magnets and a superconducting RF cavity. By July, when beamlines become operational, currents up to 100 mA with 4 hour lifetimes are expected.  
 
THPKF015 Compressed Electron Bunches for THz-Generation - Operating BESSY II in a Dedicated Low Alpha Mode optics, radiation, electron, single-bunch 2290
 
  • G. Wustefeld, J. Feikes, K. Holldack, P. Kuske
    BESSY GmbH, Berlin
  For the first time an electron storage ring was operated during regular user shifts in a dedicated 'low alpha' mode, where electron bunches are compressed to 5 times shorter length for THz [*] and short X-ray pulses experiments. The 1 mm rms-long bunches emit powerfull, coherent THz waves, up to 107 times stronger than incoherent radiation. We report on machine set up and operating experience.

* M. Abo-Bakr et al., Phys. Rev. Lett. 88, 254801 (2002)

 
 
THPKF024 A STATE-OF-THE-ART 3 GEV BOOSTER FOR ASP booster, septum, lattice, injection 2317
 
  • G. Georgsson, N. Hauge
    Danfysik A/S, Jyllinge
  • S.P. Møller
    ISA, Aarhus
  DANFYSIK A/S will build the full-energy booster for the Australian Synchrotron Project. The Booster will accelerate the beam from the injection energy of 100 MeV to a maximum of 3.0 GeV. The Booster shall accelerate either a single bunch or a bunch train up to 150 ns. The current accelerated to 3 GeV will be in excess of 0.5 and 5 mA for the two modes, respectively. The circumference of the Booster is 130.2 m, and the lattice will have four-fold super-symmetry with four straight sections for RF, injection, special diagnostics and extraction. The lattice is designed to have many cells with combined-function magnets (dipole, quadrupole and sextupole fields) in order to reach a very small emittance of around 30 nmrad. A small emittance is beneficial, in particular for top-up operation. Details of the lattice design and beam dynamics of the booster will be presented.  
 
THPKF026 An Update on the SESAME Light Source lattice, quadrupole, dipole, dynamic-aperture 2323
 
  • D. Einfeld
    CELLS, Bellaterra (Cerdanyola del Vallès)
  • M. Attal, G. Vignola
    SESAME, Amman
  During the past three years, the SESAME machine design has been optimised gradually taking into consideration the users demand in the Middle East region. The earlier design concept was to upgrade BESSY I to an energy of 1GeV, now SESAME is a 2.5GeV 3rd generation light source. A recent design review has recommended changing the machine lattice and layout to give greater flexibility for future upgrading and modification, the longest possible beam lines and the longest possible insertion devices, all of that with the limitation of the space available for the machine within the building. By shifting the machine by 6m from the centre of the building (in one direction) it was possible to increase the circumference of the storage ring by 3.6m into 128.4m and beam lines with lengths of 37.7m achieved, while the longest beam line in the old design was only 33.1m, this also increased the total length of the beam lines from 378.2m in the old design into 391.0m. An outline of these optimisations with their influence on the machine output is presented here. Furthermore the beam dynamics, the design of the main components of the storage ring and the first set of beam lines will be discussed.  
 
THPKF030 Progress Report on the construction of SOLEIL dipole, storage-ring, quadrupole, booster 2335
 
  • J.-M. Filhol
    SOLEIL, Gif-sur-Yvette
  The construction of SOLEIL, the French new SR facility, was launched in Jan 2002. The construction of the building has started in Aug 2003 and will enable a progressive beneficial occupancy from summer 2004 onwards. It is foreseen to achieve the commissioning of the 100 MeV Linac by the end of 2004, of the 3 Hz Booster in spring 2005 and of the 2.75 GeV Storage Ring by the end of 2005. All the major components have been ordered and some have already been delivered : the Booster and SR dipole magnets, the Linac sections and the Booster RF cavity. Some innovative development have been initiated specifically for SOLEIL: A 352 MHz SC RF cavity, solid state RF amplifiers for the Booster (40 kW) and the Ring (2 x 190 kW), BPM digital electronics, Al NEG coated vacuum vessels for all straight parts of the ring, or electromagnetic undulators to provide high brilliance polarized light in the VUV range. In order to provide the best performances, significant attention was paid at each design stage (optics, magnets, BPM, vacuum and RF systems,..), involving a large effort of simulation, using 6D tracking codes, or evaluating in detail the contribution of each component to the machine impedance.

on behalf of the SOLEIL project team

 
 
THPKF071 Linear Coupling and Lifetime Issues in the DIAMOND Storage Ring coupling, quadrupole, emittance, storage-ring 2430
 
  • R. Bartolini
    Diamond, Oxfordshire
  • N.G. Wyles
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  In synchrotron light sources the correction of the linear coupling is an important issue related to the brightness of the photon beam and to the beam lifetime. The vertical emittance of the electron beam in the DIAMOND storage ring will be controlled using 168 skew quadrupoles embedded in the sextupoles of the ring. In this paper we report the linear coupling estimates for the expected misalignment errors and we compare the results of coupling correction with different correction strategies. The effect on lifetimes is also discussed.  
 
THPLT072 Magnet and RF Systems of Small Pulse Synchrotron for Radiotherapy dipole, quadrupole, synchrotron, proton 2661
 
  • K. Endo, K. Egawa, Z. Fang, S. Yamanaka
    KEK, Ibaraki
  To cure the malignant tumor it is desirable to equalize the treatment level to everybody anywhere he lives in. Proton and/or carbon-ion therapy are now considered as a powerful remedy as the radiation dose can be easily concentrated to the target volume by utilizing the Bragg?s peak. If a small medical accelerator is developed at a reasonable cost, it has a big potential to promote the advanced medical treatment with the accelerator in every place. This pulse synchrotron aims to reduce the size of the accelerator by generating the high magnetic field in a short time which leads to a compact ring of high field magnets. Acceleration time is only 5 msec by using the discharge current of a capacitor bank as large as 200 kA at peak, almost equivalent to half sinusoidal 50 Hz. Part of the discharge current is branched to excite the quadrupole magnets to assure the tracking between the dipole and quadrupole fields. Pulsed power technique is also adopted to drive the RF power tubes. Both magnet and RF systems have been developed and being extensively studied. Technological sides of both systems will be treated in details as well as the computational beam behaviors in this pulse synchrotron.  
 
THPLT166 Development of Injection and Optics Control Applications for the SNS Accumulator Ring injection, optics, linac, quadrupole 2849
 
  • S.M. Cousineau, C. Chu, J. Galambos, S. Henderson, T. Pelaia, M. Plum
    ORNL/SNS, Oak Ridge, Tennessee
  • A.L. Leahman
    WSSU, Winston-Salem, North Carolina
  A large suite of physics software applications is being developed to facilitate beam measurement and control in the SNS accumulator ring. Two such applications are an injection control and measurement application, and a ring optics control application. The injection application will handle measurement and control of the linac beam position and angle at the stripper foil, and will be used to measure the twiss parameters of the linac beam at the foil. The optics control application will provide knobs for machine working point, chromaticity, arc phase advance, and harmonic correction. Both applications are written within the standard in-house XAL framework. Presented here are first versions of the applications, along with plans for future development and testing.  
 
THPLT179 MADX-UAL Suite for Off-line Accelerator Design and Simulation simulation, quadrupole, optics, space-charge 2873
 
  • N. Malitsky, R.P. Fliller III, F.C. Pilat, V. Ptitsyn, S. Tepikian, J. Wei
    BNL, Upton, Long Island, New York
  • F. Schmidt
    CERN, Geneva
  • R.M. Talman
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  We present here an accelerator modeling suite that integrates the capability of MADX and UAL packages, based on the Standard eXchange Format (SXF) interface. The resulting environment introduces a one-stop collection of accelerator applications ranging from the lattice design to complex beam dynamics studies. The extended capabilities of the MADX-UAL integrated approach have been tested and effectively used in two accelerator projects: RHIC, where direct comparison of operational and simulated data is possible, and the SNS Accumulator Ring, still in its design phase.