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MOPKF058 Construction of an APPLE-II Type Undulator at Daresbury Laboratory for the SRS undulator, vacuum, radiation, insertion-device 440
 
  • F.E. Hannon, J.A. Clarke, C. Hill, A.A. Muir, D.J. Scott, B.J.A. Shepherd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  A new variable polarisation undulator of the APPLE-II type has been designed and constructed at Daresbury Laboratory. Testing of the 56mm period device has recently started in the new Magnet Test Facility at Daresbury Laboratory. This paper presents the magnetic and mechanical design of the undulator, and the first magnetic measurement results.  
 
MOPKF069 Engineering Design of the LUX Photoinjector klystron, vacuum, impedance, emittance 473
 
  • J.W.  Staples, S.P. Virostek
    LBNL, Berkeley, California
  • S.M. Lidia
    LBNL/AFR, Berkeley, California
  The photoinjector for the LBNL LUX project, a femtosecond-regime X-ray source, is a room-temperature 1.3 GHz 4-cell structure producing a 10 MeV, nominal 30 psec, 1 nanocoulomb electron bunch at a 10 kHz rate. The first cell is of reentrant geometry, with a peak field of 64 MV/m at the photocathode surface, the geometry of which will be optimized for minimum beam emittance. The high repetition rate and high peak power results in a high average surface power density. The design of the cavity, its cooling structure and power couplers, is coordinated with the configuration of the RF system, including a short, high-power driving pulse and active removal of stored energy after the beam pulse to reduce the average power dissipated in the cavity. An RF and thermal analysis will be presented, along with plans for a high average and peak power test of the first cell.  
 
MOPKF076 An Overview of the Cryomodule for the Cornell ERL Injector linac, emittance, damping, synchrotron 491
 
  • H. Padamsee, B.M. Barstow, V. Medjidzade, V.D. Shemelin, K.W. Smolenski
    Cornell University, Ithaca, New York
  • I. Bazarov, C.K. Sinclair
    Cornell University, Department of Physics, Ithaca, New York
  • S.A. Belomestnykh, R. Geng, M. Liepe, M. Tigner, V. Veshcherevich
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  The first stage of the Cornell ERL project will be a 100 MeV, 100 mA (CW) prototype machine to study the energy recovery concept with high current, low emittance beams. In the injector, a bunched 100 mA, 500 keV beam of a DC gun will be compressed in a normal-conducting copper buncher and subsequently accelerated by five superconducting 2-cell cavities to an energy of 5.5 MeV. We will present an overview of the injector status to include the status of the cryomodule design along with the status of the 2-cell HOM-free cavity, the twin-input coupler and the ferrite HOM dampers in related papers.  
 
MOPLT024 Flexibility, Tolerances, and Beam-Based Tuning of the CLIC Damping Ring betatron, damping, closed-orbit, sextupole 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.  
 
MOPLT054 High Current Operation of Pre-bunching Cavities in the CTF3 Accelerator beam-loading, simulation, klystron, gun 674
 
  • R. Roux, G. Bienvenu
    LAL, Orsay
  • E. Jensen
    CERN, Geneva
  In the framework of the CLIC studies for a 3 TeV centre of mass linear collider the CLIC Test Facility-3 accelerator (CTF3) is developed to validate the novel concept of CLIC drive beam generation. The front end of the CTF3 linac uses a 140 kV thermionic gun capable to deliver a beam with currents of up to 10 A during 1.5 microseconds. Theμtime structure of this beam is generated with two standing wave single-cell 3 GHz pre-buncher cavities. The high current demands special care in the design of the pre-bunchers to preserve beam quality and transmission. A particular concern was beamloading in the second pre-buncher. In this paper, the design and the conditioning of the pre-bunchers are reported but the main focus is on the commissioning with the electron beam, which showed unexpected results. Indeed, contrary to our expectations, the unbunched beam seems to induce a kind of beamloading in the first pre-buncher while the second one shows none.  
 
MOPLT059 Design Options for the RF Deflector of the CTF3 Delay Loop klystron, simulation, polarization, linac 689
 
  • F. Marcellini, D. Alesini
    INFN/LNF, Frascati (Roma)
  Injection and extraction of bunch trains in the CTF3 Delay Loop for the recombination between adjacent bunch trains is performed by a specially designed RF deflector. A standing wave structure has been chosen. Three possible solutions have been studied and designed, and a comparative analysis is presented. All of them satisfy the essential requirements of the system up to the maximum foreseen energy with the existing klystron.  
 
MOPLT060 New RF Measuring System for Cavity Characterization pick-up, controls, superconductivity, monitoring 692
 
  • S. Stark, G. Bisoffi, l. Boscagli, V. Palmieri, A.M. Porcellato
    INFN/LNL, Legnaro, Padova
  New computer based mobile measuring system for laboratory and online characterization of superconducting cavities has been put into operation at LNL. The system covers the frequency range from 80 to 350 MHz and represents a reliable, fast and precise instrument for cavity testing. The list of automatic and semiautomatic procedures includes line calibrations, frequency sweep, decay time measurement, Q(Eacc) curve acquisition and pulse conditioning.  
 
MOPLT078 The Coupling Compensation and Measurement in the Interaction Region of BEPCII quadrupole, simulation, luminosity, interaction-region 728
 
  • C.H. Yu, G. Xu
    IHEP Beijing, Beijing
  The detector solenoid field in the BEPCII interaction region will be compensated by 6 anti-solenoids, which are located nearby the interaction point. The coupling compensation scheme and the method to tune the x-y coupling at the interaction point will be introduced in detail.  
 
MOPLT092 Single Mode RF Cavity for VEPP-2000 Storage Ring Based Collider storage-ring, damping, impedance, luminosity 752
 
  • V. Volkov, A. Bushuev, E. Kenjebulatov, I. Koop, A. Kosarev, Ya.G. Kruchkov, S.A. Krutikhin, I. Kuptcov, I. Makarov, N. Mityanina, V. Petrov, E. Rotov, I. Sedlyarov, Y.M. Shatunov
    BINP SB RAS, Novosibirsk
  Accelerating cavity 172 MHz with strong damped higher-order modes (HOM) for VEPP-2000 electron-positron collider have been made in Novosibirsk. Resonance frequences and Q values of cavity HOMs are measured and analysed. Most of HOMs have Q values less than 300. We compare these results with computer calculations of HOM.  
 
MOPLT121 Water Flow Vibration Effect on the NLC RF Structure-girder System RF-structure, linac, quadrupole, simulation 821
 
  • C. Boffo, T.T. Arkan, E. Borissov, H. Carter
    Fermilab, Batavia, Illinois
  • F. Le Pimpec, A. Seryi
    SLAC, Menlo Park, California
  In order to meet the vibration budget for the Next Linear Collider main Linac components, the vibration sources in the NLC girder are being studied. The activity is focused on the vibration induced by the cooling water flow for the 60 cm long accelerating copper structures. Understanding the vibration in the structures will enable us to push forward the design of the interface between the structures and the quadrupoles. This paper reports on the ongoing work and presents results from experimental data as well as finite element simulations.  
 
MOPLT129 Identifying Lattice, Orbit, and BPM Errors in PEP-II betatron, emittance, lattice, luminosity 839
 
  • F.-J. Decker
    SLAC, Menlo Park, California
  The PEP-II B-Factory is delivering peak luminosities of up to7.4·1033 1/cm2 1/s. This is very impressive especially considering our poor understanding of the lattice, absolute orbit and beam position monitor system (BPM). A few simple MATLAB programs were written to get lattice information, like betatron functions in a coupled machine (four all together) and the two dispersions, from the current machine and compare it the design. Big orbit deviations in the Low Energy Ring (LER) could be explained not by bad BPMs (only 3), but by many strong correctors (one corrector to fix four BPMs on average). Additionally these programs helped to uncover a sign error in the third order correction of the BPM system. Further analysis of the current information of the BPMs (sum of all buttons) indicates that there might be still more problematic BPMs.  
 
MOPLT142 Analysis of KEK-ATF Optics and Coupling Using LOCO quadrupole, emittance, sextupole, 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.  
 
MOPLT155 Study of Beam-beam Effects at PEP-II luminosity, simulation, damping, positron 896
 
  • I.V. Narsky, F.C. Porter
    CALTECH, Pasadena, California
  • Y. Cai, J. Seeman
    SLAC, Menlo Park, California
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  Using a self-consistent, three-dimensional simulation program running on parallel supercomputers, we have simulated the beam-beam interaction at the PEP II asymmetric e+e- collider. In order to provide guidance to luminosity improvement in PEP-II, we have scanned the tunes and other machine parameters in both rings, and computed their impact on the luminosity and particle loss. Whenever possible, the code has been benchmarked against experimental measurements, at various beam currents, of luminosity and luminous-region size using the BaBar detector. These studies suggest that three-dimensional effects such as bunch lengthening may be important to understand a steep drop of luminosity near the peak currents.  
 
MOPLT163 Luminosity Optimization Using Automated IR Steering at RHIC luminosity, background, feedback, electron 911
 
  • K.A. Drees, T. D'Ottavio
    BNL, Upton, Long Island, New York
  The goal of the RHIC 2004 Au-Au run was to maximize the achieved integrated luminosity. One way is to increase beam currents and minimize beam transverse emittances. Another important ingredient is the minimization of time spent on activities postponing the declaration of 'physics conditions', i.e. stable beam conditions allowing the experimental detectors to take data. Since collision rates are particularly high in the beginning of the store the integrated luminosity benefits considerably from any minute saved early in the store. In the RHIC run 2004 a new IR steering application uses luminosity monitor signals as a feedback for a fully automated steering procedure. This report gives an overview of the used procedure and summarizes the achieved results.  
 
TUPKF002 TRIUMF ISAC II RF Control System Design and Testing controls, feedback, linac, target 953
 
  • M.P. Laverty, S.F. Fang, K. Fong
    TRIUMF, Vancouver
  The rf control system for the ISAC II superconducting cavities is a hybrid analogue/digital design which has undergone several iterations in the course of its development. In the current design, the cavity operates in a self-excited feedback loop, while phase locked loops are used to achieve frequency and phase stability. Digital signal processors are used to provide amplitude and phase regulation, as well as mechanical cavity tuning control. The most recent version also allows for the rapid implementation of operating firmware and software changes, which can be done remotely, if the need arises. This paper describes the RF control system and the experience gained in operating this system with a four-cavity test facility.  
 
TUPKF007 Series Fabrication Technologies for Normalconducting Linac and Storage Ring Cavities vacuum, linac, alignment, RF-structure 968
 
  • P. vom Stein, K. Dunkel, B. Griep, C. Piel, H.P. Vogel
    ACCEL, Bergisch Gladbach
  Twelve HOM damped 476 MHz single cell cavities have been delivered for PEP II and the production of several 805 MHz CCL modules for SNS has recently been finalised by ACCEL Instruments. Based on those two examples, required key technologies for cavity production will be introduced. Final prove of successful manufacturing is given by low level rf measurements. Results of those measurements for above mentioned projects will be presented within this paper.  
 
TUPKF011 First Tests of a HOM-Damped High Power 500MHz Cavity impedance, vacuum, damping, simulation 979
 
  • F. Marhauser, E. Weihreter
    BESSY GmbH, Berlin
  A prototype high power 500 MHz copper cavity with three tapered circular waveguides for broadband higher order mode (HOM) damping has been fabricated especially for the use in 3rd generation synchrotron radiation sources. Low power impedance measurements are presented and compared with theoretical simulations to verify the expected HOM damping efficiency as well as the fundamental mode shunt impedance. After a careful cleaning and baking process to reduce the vacuum pressure the cavity has been conditioned at high power. All relevant parameters of the cavity are reported.  
 
TUPKF012 A HOM Damped Planar Accelerating Structure damping, dipole, impedance, polarization 982
 
  • A. Blednykh, H. Henke
    TET, Berlin
  The problem of very fast higher order mode (HOM) suppression, in the order of 1ns, was investigated for a planar 30GHz accelerating structure. Both, damping and detuning were considered. A sufficient suppression could be achieved by damping waveguides in every cell in vertical and in horizontal direction. Finally, a scaled-up 10GHz model was built. It is a 35 cm long aluminum structure, which was machined by high-precision milling. In order to reduce the surface gradient on the input/output coupling irises a symmetrical RF coupler was developed. The HOM damping is accomplished by coupling six damping waveguides to each accelerating cell. The waveguides are loaded by a low resitivity RF load. The whole structure with waveguides and loads was optimized by means of the computer code GdfidL. The paper gives the design criteria and the results of s-parameter and bead-pull measurements.  
 
TUPKF014 Electromagnetic Design of New RF Power Couplers for the S-DALINAC electron, electromagnetic-fields, emittance, linac 988
 
  • M. Kunze, W.F.O. Müller, T. Weiland
    TEMF, Darmstadt
  • M.B. Brunken, H.-D. Gräf, A. Richter
    TU Darmstadt, Darmstadt
  New rf power couplers for the Superconducting Darmstadt Linear Accelerator (S-DALINAC) injector have to be designed to transfer rf power up to 2 kW to the electron beam. This allows injector operation at beam currents from 0.15 mA to 0.2 mA and electron energies up to 14 MeV. The new couplers should possibly provide a variable external Q in the range from 5·106 to 3·109 and a small transverse kick. A variable coupling is needed to allow for perfect matching in the case of beam loading and when no beam is present, respectively. The second operation stage is used for cavity diagnostics. The asymmetric field distribution of the couplers generates emittance growth of the electron beam and therefore the transverse kick has to be minimized. Electromagnetic simulations are applied to investigate different coupler designs and to localize possible problems at an early stage. Cavity external Q and transverse kick can be calculated from 3D electromagnetic eigenmode solutions. The present coaxial-coaxial input couplers at the S-DALINAC are limited to power operation below 500 W under full reflection. Therefore, to reach power operation up to 2 kW two possible new realizations of low-kick waveguide couplers for the S-DALINAC injector are presented, namely a single-waveguide and a twin-waveguide coupler.  
 
TUPKF016 Dynamic Lorentz Force Detuning Studies in TESLA Cavities linac, resonance, beam-loading, acceleration 994
 
  • V. Ayvazyan, S. Simrock
    DESY, Hamburg
  Dynamic detuning of the superconducting rf cavities due to Lorentz force induced mechanical excitation is a critical concern since the magnitude can approach the cavity bandwidth and require significant additional rf power for field control. In this paper, the influence of high accelerating fields on the resonance frequency in superconducting TESLA cavities is discussed. Cavities at the TESLA Test Facility have been operated at the design operating gradient close to 25 MV/m. It is shown that Lorentz force detuning constant factors are different for different cavities, significant spread have been observed.  
 
TUPKF020 Numerical Investigation on the ELETTRA 500 MHz Power Coupler vacuum, simulation, electron, storage-ring 1006
 
  • C. Pasotti, P. Craievich, A. Fabris, G. Penco, M. Svandrlik
    ELETTRA, Basovizza, Trieste
  • B. B. Baricevic
    DEEI, Trieste
  Due to the high input power required to feed a resonant cavity, the RF input coupler is a critical component for the reliability of an RF system. The 500 MHz RF input coupler for the ELETTRA cavities was specified for 150 kW input power. It is important to investigate the performance limits of the coupler in view of increasing RF power requirements. The coupler's maximum peak field and dissipation versus the input power have been studied by means of the numerical simulator HFSS. Possible improvements to the existing design have been investigated. The optimization has to take into consideration the following requirements: convenient power transmission efficiency, RF matching, suitable coupling coefficient, negligible perturbation on cavity voltage, moderate operating temperature and stress.  
 
TUPKF022 Constructionand Testing of the Beta=0.31, 352 MHz Superconducting Half-wave Resonator for the SPES Project linac, vacuum, quadrupole, proton 1012
 
  • A. Facco, W. Lu, F. Scarpa
    INFN/LNL, Legnaro, Padova
  • E. Chiaveri, R. Losito
    CERN, Geneva
  • V. Zviagintsev
    TRIUMF, Vancouver
  The interest in low- and medium- beta superconducting cavities is presently focused to future high intensity proton, deuteron and heavy ion linacs. A particular application is acceleration of cw and pulsed beams of variable q/A, which requires cavities with a small number of gaps and excellent mechanical stability. We have designed and constructed a 2 gap, 352 MHz SC half wave cavity aiming to similar characteristics and fitting the requirements of the intermediate-beta section of the LNL-SPES driver. The status of the project and the first test results will be presented.  
 
TUPKF036 RF Property of the Prototype Cryomodule for ADS Superconducting Linac linac, vacuum, simulation, proton 1042
 
  • E. Kako, S. Noguchi, N. Ohuchi, T. Shishido
    KEK, Ibaraki
  • N. Akaoka, H. Kobayashi, N. Ouchi, T. Ueno
    JAERI/LINAC, Ibaraki-ken
  • H. Hara, M. Matsuoka, K. Sennyu
    MHI, Kobe
  A prototype cryomodule containing two 9-cell superconducting cavities of beta=0.725 and frequency=972MHz is being constructed under the collaboration of Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK) on the development of superconducting LINAC for Accelerator Driven System (ADS). Design and performance of RF components will be reported.  
 
TUPKF039 The Experiences of Operation and Performance about the 500 MHz CW Klystrons at the PLS Storage Ring klystron, storage-ring, electron, cathode 1051
 
  • J.S. Yang, M.-H. Chun, Y.J. Han, S.-H. Nam, I.H. Yu
    PAL, Pohang
  There are four RF stations to supply the energy to electron at the storage ring of the Pohang Light Source(PLS). From the beginning of the operation of RF system, 500MHz 60kW(CW) klystrons have been operated. As the operation time of the tubes are increased, their performances are decreased. Therefore three 60kW tubes were replaced with the same model and two 75kW klystrons were replaced with 60 kW klystrons so far. Nowadays two 75 kW and two 60 kW klystrons are operated in the RF system of PLS. Our experiences of the klystron operation and their general performance are described in this paper.  
 
TUPLT003 Transfer Matrices for the Coupled Space Charge Dominated Six-dimensional Particle Motion space-charge, lattice, storage-ring, electron 1135
 
  • D.K. Kalantaryan, Y.L. Martirosyan
    CANDLE, Yerevan
  In this paper we present exact analytical solutions for the particle motion in the six-dimensional phase space taking into account the space charge forces of fully linear coupled beam. The transfer matrices for the typical elements of magnetic lattice, such as drifts, cavities, quadrupole and dipole magnets have been obtained. The symplectic transfer matrices are used to develop a tracking program for the coupled betatron and synchro-betatron motion that enables the simulation of the tilted beam effects in circular accelerators.  
 
TUPLT039 An Electrostatic Quadrupole Doublet with an Integrated Steerer quadrupole, storage-ring, ion, focusing 1234
 
  • C.P. Welsch, M. Grieser, J. Ullrich
    MPI-K, Heidelberg
  • C. Glaessner
    IAP, Frankfurt-am-Main
  Electrostatic storage rings have proven to be a valuable tool for atomic and molecular physics Due to the mass independence of the fields in the bending and focusing elements, different kinds of ions with the same charge/energy ratio from light protons to very heavy biomolecules, can be stored with the same field setup. The transverse dimensions of the circulating beam are controlled by electrostatic quadrupole doublets or triplets. It is essential that the fields in these lenses can be adjusted independently one from another to allow an exact control of the stored ions. In this paper, first an overview of the principle of electrostatic lenses is given. After a short discussion of fringe field effects, the results of field calculations are presented and the final layout of an electrostatic quadrupole doublet with an integrated steerer as it will be used in future electrostatic storage rings in Frankfurt and Heidelberg is discussed.  
 
TUPLT047 First Results of Pulsed Superconducting Half-wave Resonators linac, vacuum, synchrotron, resonance 1258
 
  • R. Stassen, R. Eichhorn, F.M. Esser, B. Laatsch, R. Maier, G. Schug, R. Tölle
    FZJ/IKP, Jülich
  A pulsed linac for the cooler synchrotron COSY was projected based on superconductive half-wave resonators (HWRs). The concept of single phased resonators is a great challenge related to the requirement of accelerating protons and deuterons up to a similar energy. A cryomodule, which houses four cavities was designed in Cooperation with FZJ-ZAT, taking into account the restricted space and the special requirements of a linear accelerator. Two prototypes of the 160MHz Half-Wave Resonators (HWRs) were built at different companies. The fabrication differs slightly concerning the top and bottom parts of the cavity as well as the welding of the inner and outer conductor. First results of warm and cold measurements will be presented. The behaviour of the adjustable 4kW main coupler as well as the mechanical tuner can be tested together with the HWR in a new vertical test-cryostat.  
 
TUPLT049 Triple-spoke Cavities in FZJ simulation, resonance, vacuum, proton 1261
 
  • E. Zaplatin, W. Braeutigam, R. Maier, M. Pap, M. Skrobucha, R. Stassen, R. Tölle
    FZJ/IKP, Jülich
  We report the situation with superconducting triple-spoke cavity activities at the research center FZJ in Juelich. The Nb prototype of the 700 MHz, beta=0.2 cavity is already in fabrication and should be tested this year. This work has been initiated for the European Spallation Source project. In the frames of the new European project of High Intensity Pulsed Proton Injector the 352 MHz, beta=0.48 cavity is under developments. This cavity should be designed, built and tested in the Lab within next few years.  
 
TUPLT054 Design of the Low-beta, Quarter-wave Resonator and its Cryomodule for the SPIRAL 2 Project resonance, alignment, vacuum, simulation 1276
 
  • P.-E. Bernaudin, P. Bosland, S. Chel, G. Devanz, P. Hardy, F. Michel, P. de Girolamo
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  The SPIRAL 2 project, to be built in GANIL, consists of a 40 MeV linear accelerator for 5 mA of deuterons and a target-source complex for the production of exotic isotopes. The accelerator is also optimised to accelerate q/A = 1/3 ion up to 14.4 MeV/u. The three stages of the linac are a RFQ (up to 0.75 MeV/A), a low beta (0.007) and a high beta (0.12) sections consisting of quarter-wave, 88 MHz superconducting resonators. This paper focuses on the low beta cavity and its cryomodule. The cavity nominal accelerating gradient is at least 6.5 MV/m in operation conditions. RF properties of the cavities are dealt with, as well as the mechanical ones: helium pressure effects, tunability, vibrations. The cryomodule is designed so as to save longitudinal space and therefore is partly assembled in clean room.  
 
TUPLT069 Approaching to a Mono-modal Accelerating Cavity based on Photonic Band-gap Concepts simulation, lattice, radiation, scattering 1309
 
  • M.R. Masullo
    INFN-Napoli, Napoli
  • A. Andreone, E. Di Gennaro, G. Lamura
    Naples University Federico II, Napoli
  • F. Francomacaro, M. Panniello, V.G. Vaccaro
    Naples University Federico II and INFN, Napoli
  • G. Keppel, V. Palmieri, D. Tonini
    INFN/LNL, Legnaro, Padova
  One of the main problem of high intensity accelerators is the presence of high order modes (HOMs) which might degrade the beam quality. Accelerating cavities require HOMs suppression while keeping high quality factor (Q) fundamental mode. Both these requirements can be hardly met in closed metallic cavities. In low frequency cases and for particular geometries it is possible to partially suppress HOMs, but at high frequencies and for superconducting cavities configuration becomes cumbersome and technically unviable. We propose here a high Q cavity based on Photonic Band Gap (PBG) concepts, operating in the microwave region. The cavity consists of a two-dimensional lattice, where posts (dielectric, metallic or superconducting) are sandwiched by two conducting plates. This sandwich exhibits two kinds of frequency bands: 'pass-bands' and 'stop-bands'. It is possible to localize modes in an equivalent cavity obtained by removing posts. These modes are localized in the 'cavity'. In this way, one can obtain a quasi-mono-modal cavity: high Q fundamental mode and HOMs falling into the pass bands. We will present the study, the optimisation and the measurements of our metallic (Copper) PBG structure working in the 2-20 GHz range. The development of a different cryogenic set-up, necessary to characterise an all superconducting or an hybrid (dielectric/metallic) structure, is under way.  
 
TUPLT073 Observation of Coupling Resonance in HIMAC Synchrotron resonance, electron, ion, synchrotron 1321
 
  • T. Uesugi, T. Fujisawa, K. Noda, S. Shibuya, D. Tann, H. Uchiyama
    NIRS, Chiba-shi
  • Y. Hashimoto
    KEK, Ibaraki
  • I.N. Meshkov, E. Syresin
    JINR, Dubna, Moscow Region
  Coupling resonance was observed at operating points near to Qx-Qy=1. Two-dimensional profile of a beam at its equilibrium was measured, and it was found that the beam was inclined in transverse when the operating point is near to the resonance condition. We will present the detail of the measurement and the results.  
 
TUPLT088 Beam Cooling at S-LSR laser, ion, electron, resonance 1360
 
  • A. Noda, H. Fadil, S. Fujimoto, M. Ikegami, T. Shirai, M. Tanabe, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • M. Grieser
    MPI-K, Heidelberg
  • I.N. Meshkov, E. Syresin
    JINR, Dubna, Moscow Region
  • K. Noda, T. Takeuchi
    NIRS, Chiba-shi
  • H. Okamoto, Y. Yuri
    HU/AdSM, Higashi-Hiroshima
  S-LSR is an ion accumulation and cooler ring with the circumference and maximum magnetic rigidity of 22.589 m and 1.0T.m, respectively. Electron beam cooling will be applied for laser-produced hot ion beam after phase rotation. Electron cooler for S-LSR is now under construction and the beam simulation is also going on. Laser cooling of Mg ion with low energy (35 keV) is also planned in 3-dimensional way with use of Synchro-Betatron coupling.so as to realize ultra cold beam. Cancellation of shear force due to orbit-length difference in the dipole section is to be studied with use of overlapping of the radial electric field inversely proportional to the curvature radius with the uniform vertical magnetic field. Possible experiments to approach to ultra-cold beam is also to be studied by computer simulation  
 
TUPLT140 Redesign of the ISIS Main Magnet Power Supply Storage Choke power-supply, synchrotron, insertion, proton 1455
 
  • A.J. Kimber, J.W. Gray, A. Morris
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  The ISIS facility, based at the Rutherford Appleton Laboratory in the UK, provides intense pulsed neutron and muon beams for condensed matter studies. As part of the facilities upgrade and refurbishment program, the 1MJ storage choke which forms part of the main magnet power supply system, will be replaced with a number of smaller units. The present storage choke, which consists of a split secondary winding transformer, is incorporated into a series-parallel resonant circuit known as the 'white circuit'. This circuit ensures that each magnet receives identical currents, but is not subjected to excessive voltages. Although the storage choke is essentially a transformer, its secondary magnetising inductance is relatively low and a precisely defined value. This paper discusses the design and development of ten smaller units which will eventually replace the present equipment, and the testing of a one fifth scale model, which will be used to prove the technology.  
 
TUPLT145 Transverse Coupling Measurement using SVD Modes from Beam Histories betatron, lattice, simulation, quadrupole 1470
 
  • C.-X. Wang
    ANL, Argonne, Illinois
  • R. Calaga
    BNL, Upton, Long Island, New York
  In this report we investigate the measurement of local transverse coupling from turn-by-turn data measured at a large number of beam position monitors. We focus on a direct measurement of coupled lattice functions using the Singular Value Decomposition (SVD) modes and explore the accuracy of this method. The advantages and shortcomings of this model-independent method for coupling measurement will be also discussed.  
 
TUPLT146 Techniques to Extract Physical Modes in Model-independent Analysis of Rings betatron, synchrotron, storage-ring, simulation 1473
 
  • C.-X. Wang
    ANL, Argonne, Illinois
  SVD mode analysis is a basic techinique in Model-Independent Analysis of beam dynamics. It decomposes the spatial-temporal variation of a beam centroid into a small set of orthogonal modes based on statistical analysis. Although such modes have been proven to be rather informative, each orthogonal mode may not correspond to an individual physical source but a mix of several in order to be orthogonal. Such mixing makes it difficult to quantitatively understand the SVD modes and thus limits their usefulness. Here we report a new techinique to untangle the mixed modes in storage ring analysis based on the fact that most of the physical modes in a ring have identifiable characteristics in frequency domain.  
 
TUPLT153 Orbit Response Matrix Analysis Applied at PEP-II lattice, interaction-region, sextupole, 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.  
 
TUPLT161 Normal Form Analysis of Linear Beam Dynamics in a Coupled Storage Ring lattice, betatron, storage-ring, emittance 1503
 
  • M. Woodley
    SLAC/NLC, Menlo Park, California
  • A. Wolski
    LBNL/AFR, Berkeley, California
  The techniques of normal form analysis, well known in the literature, can be used to provide a straightforward characterization of linear betatron dynamics in a coupled lattice. Here, we consider both the beam distribution and the betatron oscillations in a storage ring. We find that the beta functions for uncoupled motion generalize in a simple way to the coupled case. Defined in the way that we propose, the beta functions remain well behaved (positive and finite) under all circumstances, and have essentially the same physical significance for the beam size and betatron oscillations as in the uncoupled case. Application of this analysis to the online modeling of the PEP-II rings is also discussed.  
 
TUPLT183 Magnetized Beam Transport in Electron Coolers with Opposing Solenoid Fields electron, quadrupole, optics, ion 1556
 
  • J. Kewisch, C. Montag
    BNL, Upton, Long Island, New York
  To improve cooling capability of electron coolers magnetized beams in strong solenoid fields are used. Too avoid betatron coupling in the ion coupling compensation is required. For the RHIC electron cooler we propose a scheme consisting of two identical solenoids with opposing fields, connected by a quadrupole matching section that preserves the electron beam magnetization. Since the fringe fields of the individual magnets overlap, the matching section can not be designed with standard optics codes. We developed an optimization code based on particle tracking instead. Input for the program are the simulated/measured field maps of the magnets. We demonstrate that the transverse temperature of the electron beam does not increase.  
 
TUPLT184 Operational Measurement of Coupling by Skew Quadrupole Modulation quadrupole, injection, heavy-ion, closed-orbit 1559
 
  • Y. Luo, P. Cameron, R. Lee, A. Marusic, F.C. Pilat, T. Roser, D. Trbojevic, J. Wei
    BNL, Upton, Long Island, New York
  The measurements of betatron coupling via skew quadrupole modulation is a new diagnostics technique that has been recently developed and tested at RHIC. By modulating the current of different skew quadrupole families with different frequencies and measuring the resulting eigentunes response with a high resolution phase lock loop (PLL) system, it is possible to determine the projections of the residual coupling coefficients. We report the results of extensive beam studies carried on at RHIC injection, store energy and on the ramp. The capability of measuring coupling on the ramp opens the possibility of continuous coupling corrections during acceleration.  
 
TUPLT185 Principle of Skew Quadrupole Modulation to Measure Betatron Coupling quadrupole, simulation, injection, betatron 1562
 
  • Y. Luo, F.C. Pilat, T. Roser, D. Trbojevic, J. Wei
    BNL, Upton, Long Island, New York
  The idea of modulating Skew Qudrupoles to measure the ring betatron coupling was put forth by T. Roser. In this paper, analytical solutions for this technique is given. Simulation are also carried out based on RHIC. And other relevent issues concerning this technique's application are also discussed. All of them show this idea of modulating skew qudrupoles to measure the betatron coupling are applicable.  
 
TUPLT188 SNS Extraction Kicker Power Supply Manufacture Status power-supply, kicker, extraction, impedance 1571
 
  • J.-L. Mi, H. Hahn, R.F. Lambiase, Y.Y. Lee, C. Pai, J. Sandberg, Y. Tan, N. Tsoupas, D.S. Warburton, R. Zapasek, W. Zhang
    BNL, Upton, Long Island, New York
  There are fourteen PFN power supplies, which will be installed in the SNS Extraction Kicker System. The Pulse Forming Network (PFN) power supplies for the SNS Extraction kicker were designed by Brookhaven. The basic configuration of the PFN is a lumped element Blumlein pulse forming network (BPFN). The PFN and power supply are fabricated by an industrial company. The first article of. PFN and power supply has been manufactured and tested with a dummy load at the company and onsite with the prototype magnet. The PFN has been tested beyond its specification and has met all requirements including rise time, pulse flatness, amplitude and pulse repetition rate. Additional heat runs are scheduled. The transverse coupling impedance of the kicker system with attached PFN has been measured. This paper will report on the SNS Extraction Kicker Power Supply engineering status, and will include output waveforms, impedance measurements, and production projections.  
 
WEOACH03 Achievement of 35 MV/m in the TESLA Superconducting Cavities Using Electropolishing as a Surface Treatment linac, electron, superconductivity, collider 129
 
  • L. Lilje
    DESY, Hamburg
  The Tera Electronvolt Superconducting Linear Accelerator TESLA is the only linear electron-positron collider project based on superconductor technology for particle accelaration. In the first stage with 500 GeV center-of-mass energy an accelerating field of 23.4MV/m is needed in the superconducting niobium cavities which are operated at a temperature of 2 K and a quality factor Q0 of 1010. This performance has been reliably achieved in the cavities of the TESLA Test Facility (TTF) accelerator. The upgrade of TESLA to 800 GeV requires accelerating gradients of 35 MV/m. Using an improved cavity treatment by electrolytic polishing it has been possible to raise the gradient to 35 - 43 MV/m in single cell resonators. Here we report on the successful transfer of the electropolishing technique to multi-cell cavities. Presently four nine-cell cavities have achieved 35 MV/m at Q_0 = 5 × 109, and a fifth cavity could be excited to 39 MV/m. In two high-power tests it could be verified that EP-cavities preserve their excellent performance after welding into the helium cryostat and assembly of the high-power coupler. One cavity has been operated for 1100 hours at the TESLA-800 gradient of 35 MV/m and 57 hours at 36 MV/m without loss in performance.  
Video of talk
Transparencies
 
WEPKF031 Magnetic Field Correction of the Bending Magnets of the 1.5 GeV HDSM dipole, microtron, linac, electron 1669
 
  • F. Hagenbuck, P. Jennewein, K.-H. Kaiser
    IKP, Mainz
  Beam dynamics of the Harmonic Double Sided Microtron (HDSM), the fourth stage of MAMI, require a very precise magnetic field in the inhomogeneous bending magnets. By measuring the vertical field component By in and on both sides of the midplane, the complete set of field components Bx, By, Bz was determined in the whole gap. Starting from this the asymmetric pole surface current distribution necessary to correct both symmetric and antisymmetric field errors was calculated. However, tracking calculations showed that the influence of skewed field components on the beam deflection are negligible, so that symmetric field corrections are sufficient. Nevertheless, in order to demonstrate the functioning, a set of asymmetric correction coils was built and successfully tested. The symmetric coils are designed to reduce field errors below 2*10-4. Deflection errors in the fringe field region near the magnet corners, which cannot be corrected by surface currents, will be compensated by vertical iron shims in combination with small dipoles on each beam pipe.  
 
WEPKF053 Status and Development for the JAERI ERL-FEL for High-Power and Long-Pulse Operation linac, pick-up, feedback, undulator 1723
 
  • M. Sawamura, R. Hajima, N. Kikuzawa, E.J. Minehara, R. Nagai, N. Nishimori
    JAERI/FEL, Ibaraki-ken
  After the success of energy recovery linac (ERL) for the superconducting free-electron laser (FEL) in the Japan Atomic Energy Research Institute (JAERI), the JAERI ERL-FEL has been upgrading for high-power and long-pulse operation. The new grid pulser for the thermoionic cathode gun is under development and test to increase the beam current by increasing the repetition rate of 10MHz to 20MHz. The new RF sources of CW mode for higher power for non-energy-recovery parts have been installed and tested for long-pulse operation. The properties of the superconducting linac required for the long-pulse operation were also measured such as pressure in the cryomodule, vibration of frequency and piezo tuner response. The RF control systems have been also upgraded to reduce the fluctuation to less than 0.1% for amplitude and 0.1 deg for phase.  
 
WEPKF064 Methods for Reducing Cable Losses in Fast-Cycling Dipoles for the SIS300 Ring dipole, simulation, cryogenics 1750
 
  • L. Tkachenko, I. Bogdanov, S. Kozub, A. Shcherbakov, I. Slabodchikov, V. Zubko
    IHEP Protvino, Protvino, Moscow Region
  • G. Moritz
    GSI, Darmstadt
  • V. Sytnikov
    RCSRDI, Moscow
  A new synchrotron facility is being designed for the acceleration of high intensity and high-energy ion and proton beams at GSI, Darmstadt. The main magnetic elements of the second stage (SIS300) are superconducting dipoles with 100 mm aperture, 6-T magnetic field amplitude, and 1 T/s field ramp rate. The main requirements for these magnets, in addition to high field quality, are minimal heat losses, both in the coil and in the iron yoke, at an acceptable temperature margin. An increase of the temperature margin can be achieved by increasing the volume of superconductor in the cable. However, increasing the number of strands in the cable results in a growth of the cable width. Since coupling losses in the cable are proportional to the fourth power of cable width, these losses rise dramatically. This presentation considers and analyses different ways of reducing these cable heat losses. The calculated results of heat losses for different geometries, based on various cable designs, as well as the parameters of optimal cable designs, based on computer simulations, are presented.  
 
WEPKF066 Stability of Fast-cycling Dipole for SIS300 Ring dipole, superconducting-magnet, simulation, lattice 1756
 
  • V. Zubko, I. Bogdanov, S. Kozub, A. Shcherbakov, L. Tkachenko, S. Zintchenko
    IHEP Protvino, Protvino, Moscow Region
  • M. Kauschke, G. Moritz
    GSI, Darmstadt
  Funding AgencyShould not exceed 200 charactersFootnotesFootnotes: Not exceeding 200 chaThe main requirement to the superconducting dipole with 100-mm aperture, 6-T magnetic field amplitude and 1-T/s field ramp rate for the SIS300 accelerator, developed in the GSI, Darmstadt, is a stability of the magnet influenced by various heat releases arising during operation mode. The computer simulation of the heating of superconducting dipoles and cooling helium during the SIS300 operating cycle was carried out. The analysis of stability is based on the numerical solution of the heat balance equation in the coil and in a single?phase helium flow. Temperature margin of the superconducting dipole during the SIS300 operating cycle was calculated. Possible ways to increase the temperature margin are discussed.  
 
WEPLT003 The Study of 2D Sextupole Coupling Resonances at VEPP-4M resonance, sextupole, dynamic-aperture, 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  
 
WEPLT038 Betatron Resonance Studies at the CERN PS Booster by Harmonic Analysis of Turn-by-turn Beam Position Data resonance, injection, booster, simulation 1915
 
  • P. Urschütz, M. Benedikt, C. Carli, M. Chanel, F. Schmidt
    CERN, Geneva
  High brightness and high intensity beams are required from the PS Booster for LHC, CNGS and ISOLDE operation. The large space charge tune spreads associated with these beams, especially at injection, require an optimized resonance compensation scheme to avoid beam blow-up and subsequent beam losses. For this a detailed knowledge on strength and phase of resonance driving terms is needed. A new measurement system has been installed to determine resonance driving terms from turn-by-turn bpm data using fast Fourier transform. The multi-turn acquisition system as well as the specific measurement conditions at the PS Booster are discussed. As an example, the measurement and compensation of the linear coupling resonance driving term is presented. Excellent agreement between measurement and simulation for resonance phase and strength was found.  
 
WEPLT039 Measurement and Compensation of Second and Third Order Resonances at the CERN PS Booster resonance, booster, injection, sextupole 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.  
 
WEPLT060 Linear Coupling Theory of High Intensity Beams space-charge, resonance, emittance, simulation 1981
 
  • G. Franchetti, I. Hofmann
    GSI, Darmstadt
  • M. Aslaninejad
    IPM, Tehran
  It is planned to use linear coupling in the SIS18 in order to fully or partially equilibrate the transverse emittances before transfer to the projected SIS100 synchrotron. In this paper we show that space charge significantly modifies the coupling mechanism. In particular the width of the stop-band is dominated by the space charge tune shift for weak skew strength. The conditions are discussed, under which slow crossing of the coupling resonance leads to the desired goal of equalizing emittances while maintaining a sufficient matching of the beam to the ring and extraction optics.  
 
WEPLT072 Preliminary Design of the RF Systems for the SPIRAL 2 SC Linac linac, beam-loading, rfq, feedback 2017
 
  • M. Di Giacomo, B. Ducoudret, J.F. Leyge
    GANIL, Caen
  • J.F. Denis, M. Desmons, M. Luong, A. Mosnier
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  In the SPIRAL 2 Linac, a 5 mA, CW , Deuteron beam is accelerated up to 40 MeV, through a normal conducting RFQ and 26 independent-phase SC quarter wave resonators, working at 88,05 MHz. Tube and solid state amplifiers derived from the standard FM transmitter modules are used while a new digital control system has been designed for the feed-back and feed-forward control system. The paper presents the power and low level systems for both the normal and superconducting cavities and results of simulations of the RF system in operating conditions.  
 
WEPLT077 DESIGN OF A FULL-CUSTOM ACCURATE I-Q MODULATOR simulation, impedance, radio-frequency, insertion 2029
 
  • M. Luong, M. Desmons
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  The I-Q modulator is a key component in a digital Low Level RF (LLRF) system for amplitude and phase feedbacks. Its residual errors in offset or gain have a strong impact on the dynamic and accuracy of the feedback loops. For some frequencies, commercial I-Q modulators are available on the market. But even in that case, these components are usually designed for broadband communication purposes, and their performances in term of residual errors may not fit the strict requirements on the final amplitude and phase loop stability. Since LLRF systems for accelerators are typically narrow-banded, i.e. limited to few MHz, it is possible to achieve a high directivity and a very accurate coupling for hybrids, and an excellent matching for all subcomponents in a fully custom design. This approach guarantees the lowest residual errors for an I-Q modulator. The principle for the design and the process for the optimization are presented in this paper.  
 
WEPLT081 Numerical Evaluation of Geometric Impedance for SOLEIL impedance, vacuum, dipole, collective-effects 2041
 
  • R. Nagaoka
    SOLEIL, Gif-sur-Yvette
  Good knowledge and minimisation of the coupling impedance is of great importance for the future storage ring SOLEIL, envisaged to operate in both high current multibunch and high bunch intensity modes. Three-dimensional computations of the geometric impedance of various vacuum chamber components have been made with the code GdfidL, which allows parallel processing with a cluster of computers, rendering the computation with a small mesh size and a long integrated distance feasible. Many treated objects were found to exhibit large asymmetry in the two transverse planes, as well as resonant behaviour at high frequencies, both of which being non-straightforward to follow with the conventional analytical methods and 2-dimensional calculations. In particular, strongly trapped modes found for the flange impedance resulted in an unacceptably low vertical multibunch instability threshold, which urged a modification of the original cavity-like structure. The dependence of the dipole chamber impedance on the vertical slot size was followed to determine the optimal slot opening. Characteristics of the total broadband impedance obtained, along with relative contributions are also presented.  
 
WEPLT082 General Performances of the Injection Scheme into the SOLEIL Storage Ring injection, septum, undulator, quadrupole 2044
 
  • M.-A. Tordeux, J. Da Silva, P. Feret, P. Gros, P. Lebasque, A. Mary
    SOLEIL, Gif-sur-Yvette
  The injection scheme of the electron beam into the Storage Ring of the SOLEIL synchrotron is presented. It corresponds to the new SOLEIL optics : 12 meter long straight section, 2.75 GeV energy, with in addition the requirement for top-up injection mode. Pulsed magnets are described, and in particular the passive septum magnet, the transverse position of which can be adjusted so as to optimise the Touschek beam Lifetime. Tracking of particles has been performed over a large number of turns, taking into account the magnet errors, the high chromaticities and the physical apertures all along the machine (limited vertical apertures due to low gap undulators). Statistical efficiency of the injection has been deduced. Specific requirements for top-up injection have been examined, such as the closure of the injection bump, the residual vertical field and the leakage fields from septa.  
 
WEPLT083 Coherent and Incoherent Tune Shifts Deduced from Impedance Modelling in the ESRF-Ring impedance, vacuum, single-bunch, storage-ring 2047
 
  • T.F. Günzel
    ESRF, Grenoble
  In single bunch the detuning of the transverse modes m=0,1 and -1 are calculated on the base of an impedance model contructed from element-wise wakefield calculation and the resistive wall impedance of the ESRF-ring. As the vacuum chambers of the ESRF storage ring have notably flat cross sections incoherent wake fields have an impact on the tune shifts as well as coherent wake fields. Compared to tune shift measurements in single bunch the calculated transverse mode detuning can explain half of the tune shift in the vertical plane and almost completely the tune shift in horizontal plane.  
 
WEPLT090 Nonlinear Evolution of the Beam in Phase Space at Elettra resonance, betatron, beam-losses, dynamic-aperture 2059
 
  • S. Di Mitri, L. Tosi
    ELETTRA, Basovizza, Trieste
  Phase space in the Elettra storage ring has been investigated. The beam is kicked and the coordinates of the bunch centroid are acquired for at least 1000 turns. A Hilbert transform has been used to deduce the evolution of beam phase space from position coordinates. Several nonlinear effects have been detected, such as the amplitude dependence of the betatron tune, the presence of high order and coupling resonances. Fixed points have been evidenced as well as the behaviour of the beam in their neighbourhood. Scans in lifetime versus tune confirm the limiting effect of the observed resonances on the region of regular motion.  
 
WEPLT095 Modified Polarizabilities and Wall Impedance for Shielded Perforated Beam Pipes with General Shape impedance, vacuum, dipole, shielding 2074
 
  • S. Petracca, T. Demma
    U. Sannio, Benevento
  We extend previous results [*] concerning the modified polarizability of (electrically small) holes/slots in the wall of a circular beam liner surrounded by a coaxial circular tube to the most general liner and cold bore geometries. We obtain an equivalent wall impedance to describe the electromagnetic boundary conditions at perforated walls for this most general case, and use a general perturbational approach [**] for computing the pertinent longitudinal and transverse coupling impedances.

* R.L. Gluckstern, CERN SL 92-06 (AP), 1992, CERN SL 92-31 (AP), 1992; R.L. Gluckstern, B. Zotter, CERN SL 96-56 (AP), 1996.** S. Petracca, Part. Acc., {\bf 50}, 211, 1995; id., Phys. Rev. E, 60 (3),1999.

 
 
WEPLT108 Diffusion caused by Beam-beam Interactions with Couplings simulation, luminosity, radiation, synchrotron 2104
 
  • K. Ohmi, S. Kamada, K. Oide, M. Tawada
    KEK, Ibaraki
  A system of colliding two beams is strong nonlinear in multi-dimension. In such a system, a symplectic diffusion called Arnold diffusion occurs, with the result that the beams are enlarged and the luminosity is degraded in circular colliders. We discuss the diffusion seen in beam-beam inetraction at a circular accelerator, especially finite crossing angle and/or x-y coupling errors enhance the diffusion.  
 
WEPLT114 Field Measurements in the AGS Warm Snake dipole, resonance, simulation, betatron 2116
 
  • J. Takano, M. Okamura
    RIKEN, Saitama
  • R. Alforque, R. Belkin, G. Ganetis, A.K. Jain, W.W. MacKay, T. Roser, R. Thomas, J. Tuozzolo
    BNL, Upton, Long Island, New York
  • T. Hattori
    RLNR, Tokyo
  A new warm snake has been produced for avoiding the transverse coupling resonance in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). The warm snake is the world?s first normal conducting helical dipole partial snake which has a double pitch structure to allow spin rotation with no net beam offset or deflection with a single magnet. The warm snake is 2.6m long, and has a field of 1.5 Tesla for a 9 degrees spin rotation. The pitches, current density, and shims were optimized by using OPERA_3D / TOSCA. The magnetic field harmonics have been measured using a system of 51 mm long, 34 mm radius tangential coils. The axial variation of the dipole field angle agrees very well with the calculations, indicating no significant construction errors. However, the measured transfer function shows a discrepancy of 4% which may be caused by BH-curve differences, deformation of the iron and packing factor of the laminations. To correct the beam trajectory the operating current was adjusted and shims were installed on the end plates. These optimization studies, and comparison with measurements, will be shown.  
 
WEPLT123 Engineering Design of High-current 81.36 MHz RFQ with Elliptic Coupling Windows rfq, vacuum, alignment, ion 2143
 
  • D. Kashinskiy, A. Kolomiets, S. Minaev, V. Pershin, B.Y. Sharkov, T. Tretyakova
    ITEP, Moscow
  Four-vane RFQ structure with elliptic coupling windows has been originally developed at ITEP for injection into ITEP-TWAC synchrotron/storage ring complex, being lately adapted for RIA project too. As the electrodynamics simulations show, this structure combines the high efficiency with the operating mode stability against asymmetric detuning and electrode misalignment. A considerable reduction of structure diameter due to coupling windows becomes important for low frequency range which is necessary for the heavy ion acceleration. At the same time, the electrode configuration allows the efficient cooling and high duty factor operation. A mechanical design of 81 MHz, 1.6 MeV/u, 6 m long heavy ion RFQ section is discussed. The outer tank is made of two layers, steel and copper, joined by using the thermal diffusion technology. Each electrode is supplied with the alignment mechanism and connected to the tank by the flexible conducting insert. The whole setup is in manufacturing now.  
 
WEPLT137 Higher Order Modes in the New 100 and 500 MHz Cavities at MAX-lab damping, synchrotron, synchrotron-radiation, impedance 2158
 
  • H. Tarawneh, Å. Andersson, M. Bergqvist, M. Brandin, M. Eriksson, L. Malmgren
    MAX-lab, Lund
  The MAX-II electron storage ring operates exclusively in multi-bunch mode with all buckets filled. Damping of the longitudinal higher order mode (HOM) instabilities has successfully been provided by passive third harmonic 1.5 GHz cavities. With a new RF employing three 100 MHz capacity loaded cavities and a fifth harmonic Landau cavity installed, a study of the HOM impedances, and related threshold instability currents, is necessary. Measurements and calculations so far, are being presented.  
 
WEPLT159 Linear Vlasov Analysis for Stability of a Bunched Beam synchrotron, damping, storage-ring, synchrotron-radiation 2215
 
  • R.L. Warnock, G.V. Stupakov
    SLAC, Menlo Park, California
  • J.A. Ellison
    UNM, Albuquerque, New Mexico
  • M. Venturini
    LBNL, Berkeley, California
  We study the linearized Vlasov equation for a bunched beam subject to an arbitrary wake function. Following Oide and Yokoya, the equation is reduced to an integral equation expressed in angle-action coordinates of the distorted potential well. Numerical solution of the equation as a formal eigenvalue problem leads to difficulties, because of singular eigenmodes from the incoherent spectrum. We rephrase the equation so that it becomes non-singular in the sense of operator theory, and has only regular solutions for coherent modes. We report on a code that finds thresholds of instability by detecting zeros of the determinant of the system as they enter the upper-half frequency plane, upon increase of current. Results are compared with a time-domain integration of the nonlinear Vlasov equation, and with experiment, for a realistic wake function for the SLC damping rings.  
 
THOBCH02 DAFNE Operation with the FINUDA Experiment quadrupole, wiggler, luminosity, collider 233
 
  • C. Milardi, D. Alesini, G. Benedetti, M.E. Biagini, C. Biscari, R. Boni, M. Boscolo, A. Clozza, G.O. Delle Monache, G. Di Pirro, A. Drago, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, G. Mazzitelli, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, U. Rotundo, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, C. Vaccarezza, M. Vescovi, M. Zobov
    INFN/LNF, Frascati (Roma)
  DAFNE operation restarted in September 2003, after a six months shut-down for the installation of FINUDA, a magnetic detector dedicated to the study of hypernuclear Physics. FINUDA is the third experiment running, in sequence, at DAFNE and operates while keeping on place the other detector KLOE. During the shut-down both the Interaction Regions have been equipped with remotely controlled rotating quadrupoles in order to operate at different solenoid fields. Among many other hardware upgrades one of the most significant is the reshaping of the wiggler pole profile to improve the field quality and the machine dynamic aperture. Commissioning of the collider in the new configuration has been completed in short time. The peak luminosity delivered to FINUDA has reached 6 1031 s-1 cm-2, with a daily integrated value exceeding 3 pb-1.

Work presented by C. Milardi on behalf of the DAFNE Team

 
Video of talk
Transparencies
 
THPKF006 Lifetime Studies in the LNLS Electron Storage Ring storage-ring, scattering, synchrotron, single-bunch 2266
 
  • N.P. Abreu, P.F. Tavares
    LNLS, Campinas
  In this paper we present a set of measurements performed at the 1.37 GeV electron storage ring of the Brazilian Synchrotron Light Source. We measured the beam lifetime as a function of: current per bunch, gap voltage and position of horizontal and vertical scrapers. Those measurements helped us to determine the contribution of various particle loss mechanisms (Touschek, elastic and inelastic scattering and quantum fluctuations) to the lifetime of the beam. Comparison with theory is also presented as well as an interpretation of each effect.  
 
THPKF036 Developments of the FZP Beam Profile Monitor damping, alignment, radiation, background 2353
 
  • N. Nakamura, M. Fujisawa, H. Kudo, H. Sakai, K. Shinoe, H. Takaki, T. Tanaka
    ISSP/SRL, Chiba
  • H. Hayano, T. Muto
    KEK, Ibaraki
  A beam profile monitor based on two Fresnel Zone Plates (FZPs) has been developed at the KEK-ATF damping ring. This monitor can perform real-time imaging of the electron beam with an X-ray imaging optics and the synchrotron radiation and measure the horizontal and vertical beam sizes with a high spatial resolution. A clear electron-beam image with the vertical beam size less than 10 microns was already obtained in the early measurements [*]. Thereafter some of the optical elements, the crystal monochromator, X-ray CCD camera and FZP holders, were improved and an X-ray pinhole mask was installed between the two FZPs for reducing the background of X-rays passing through the MZP (the second FZP). Aberrations due to alignment errors of the FZPs were studied with an analytical approach and a ray-tracing method and vibrations of the optical elements were measured in order to estimate their effects on the system performance. In this paper, we will present developments of the beam profile monitor with results of some beam-size measurements.

* K. Iida et al., Nucl. Instrum. Methods A506, p.41-49 (2003); N. Nakamura et al., Proc. of PAC2003, p.530-532

 
 
THPKF045 Accelerator Physics Issues at NSRRC insertion, insertion-device, injection, synchrotron 2377
 
  • C.-C. Kuo, H.-P. Chang, P.J. Chou, K.-T. Hsu, G.-H. Luo, H.-J. Tsai, M.-H. Wang
    NSRRC, Hsinchu
  Over the past decade, NSRRC has served the synchrotron light users with its 1.5 GeV third-generation storage ring. To provide stable hard x-ray for the x-ray community, two strong-field superconduting wigglers have been installed and three more will be put in such a low energy ring. A superconduting rf cavity is to replace the conventional ones and the beam current will be double too. Top-up injection study is underway. This paper presents the accelerator physics issues at NSRRC such as single particle dynamics and collective effects.  
 
THPKF050 Electron Accelerator for Energy up to 5.0 MeV and Beam Power up to 50 KW with X-ray Converter electron, vacuum, extraction, cathode 2383
 
  • V. Auslender, A.A. Bryazgin, B.L. Faktorovich, E.N. Kokin, I. Makarov, S.A. Maximov, V.E. Nekhaev, A.D. Panfilov, V.M. Radchenko, M.A. Tiunov, V.O. Tkachenko, A.F.A. Tuvik, L.A. Voronin
    BINP SB RAS, Novosibirsk
  In recent time the new powerful industrial electron accelerators appear on market. It caused the increased interest to radiation technologies using high energy X-rays due to their high penetration ability. One of the promising directions is the creation of the irradiation installations for treatment of wide variety of food products. The report describes the industrial electron accelerator ILU-10 for electron energy up to 5 MeV and beam power up to 50 kW specially designed for use in industrial applications. The ILU-10 accelerator generates the vertical electron beam. The beam line turns the beam through an angle of 90 degrees and transports the beam to the vertically posed X-ray converter to generate the horizontal beam of X-rays. In the work presented results of measurements of the dose distribution profiles on the surface of treated products.  
 
THPKF067 Progress of the DIAMOND Storage Ring and Injector Design. injection, storage-ring, booster, septum 2418
 
  • S.L. Smith, D.J. Holder, J.K. Jones, J.A. Varley, N.G. Wyles
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R. Bartolini, I.P.S. Martin, B. Singh
    Diamond, Oxfordshire
  DIAMOND is a state of the art 3 GeV synchrotron light source that will be available to users in 2007. Considerable further progress has been made on the accelerator physics design of the storage ring, booster and other associated injector systems. Detailed analysis of injection processes, lifetime, coupling, instabilities, feedback systems and dynamic aperture have been undertaken driven by the procurement activity and the desire to fully understand all aspects of the accelerator's performance.  
 
THPKF071 Linear Coupling and Lifetime Issues in the DIAMOND Storage Ring quadrupole, emittance, storage-ring, sextupole 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.  
 
THPLT014 Coupler Structures for the LHC Beam-pipe Waveguide Mode Reflectometer higher-order-mode, vacuum, simulation, dipole 2493
 
  • T. Kroyer
    TU Vienna, Vienna
  • F. Caspers
    CERN, Geneva
  The LHC reflectometer will be used to detect and localize obstacles and other kinds of discontinuities in the LHC beam screen. An important part of this device is the RF coupler element, which provides the interface between the circular beam screen and the measurement equipment. Two different scenarios of operation are considered. The first option consists in carrying out measurements during assembly by directly branching a coupler to the end of the beam screen. The other one is a permanent installation to be used in situ requiring a different kind of coupler to keep the aperture free. The goal is to achieve a reasonably well-matched spurious mode-free excitation over a 25% bandwidth for the TM01 and the T·1011 mode, respectively. The fulfillment of the required features is severely complicated by space and material restrictions arising mainly from vacuum and installation constraints.  
 
THPLT028 High Precision Cavity Beam Position Monitor dipole, resonance, background, damping 2535
 
  • A. Liapine, H. Henke
    TET, Berlin
  A cavity beam position monitor is proposed for measuring the beam deflection in the TESLA energy spectrometer. The precision of the measurement has to be better than 1 micrometer. A slotted cavity is chosen as pick-up in order to reject the background signals and enhance the precision and the dynamic range of the monitor. The paper gives the design overview for two prototypes with operating frequencies of 1.5 GHz and 5.5 GHz, respectively. The results obtained on the test bench with direct conversion electronics are presented. A resolution of about 100 nm was achieved.  
 
THPLT083 Femto-second Bunch Length Measurement using the RF Deflector electron, dipole, radiation, linac 2691
 
  • S. Kashiwagi, G. Isoyama, R. Kato, K.K. Kobayashi, Y. Matsui, A. Saeki, J. Yang
    ISIR, Osaka
  • H. Hayano, M. Kuriki
    KEK, Ibaraki
  • M. Kudo, M. Washio
    RISE, Tokyo
  The traveling wave type rf cavities operating in dipole mode (TM110-like) is being developed for a measurement of femto-second electron bunch. The femto-second electron bunch is used the pulse radiolysis experiments for the studies on radiation physics and chemistry with femto-second time resolution. The resonant frequency is tuned to the designing value 2856 MHz, which is accelerating frequency of a photo-injector linac at ISIR Osaka University. Further, we are planning to apply the design of the traveling wave rf deflector to a X-band crab cavities for the Global Linear Collider (GLC) project. In this conference, we will report the design of the traveling wave rf deflector and the result of cold test.  
 
THPLT085 Reengineering and Refactoring Large-scale Scientific Programs with the Unified Process: A Case Study with OSIRIS PIC Program diagnostics, simulation, factory, electromagnetic-fields 2697
 
  • J.B.  Kim, I.S. Ko
    POSTECH, Pohang, Kyungbuk
  • H. Suk
    KERI, Changwon
  As science and engineering problems get more complex, programs which help modelling complicated problems larger and more sophisticated. This trend makes us recognize the importance of well-established engineering disciplines not only in designing large-scale scientific programs for special purposes in appropriate development time but also in importing the programs from other research group and refactor it for conveniences and more advanced applications. OSIRIS is a large-scale PIC code which was developed at UCLA for modelling of laser-plasma interactions. OSIRIS was reengineered and documented in UML by our group and ported to Linux cluster machine of 8 nodes. We report our current status of developing the extended version of OSIRIS, which was named as OSIRIS-X, and how a large-scale scientific programs can be enhanced efficiently with the Unified Process. Some guidelines in designing and refactoring large-scale scientific codes are presented and discussed. A common architecture model of numerically intensive programs for large-scale computing is suggested , and it is discussed how we can use it for rapid development and prototyping of scientific programs. We also discuss future challenges and prospects in OSIRIS-X development.  
 
THPLT086 High Temporal Resolution, Single-shot Electron Bunch-length Measurements electron, laser, undulator, monitoring 2700
 
  • G. Berden, B. Redlich, A.F.G. Van der Meer
    FOM Rijnhuizen, Nieuwegein
  • W.A. Gillespie, A. MacLeod
    UAD, Dundee
  • S.P. Jamison
    Strathclyde University, Glasgow
  A new technique, combining the electro-optic detection of the Coulomb field of an electron bunch and the single-shot cross-correlation of optical pulses, is used to provide single-shot measurements of the shape and length of sub-picosecond electron bunches. As in our previous technique [I. Wilke et al., Phys. Rev. Lett. 88, 124801 (2002)], the electric field of the electron beam is encoded electro-optically on an optical pulse. Our earlier measurements, which involved encoding the time profile of the electron bunch on the spectrum of the optical pulse, showed electric field profiles with a FWHM of the order of 1.7 ps. The new method offers a much better time resolution since it avoids the significant measurement artifacts that can arise in our previous (spectral encoding technique due to the coupling between the temporal envelope and spectral content of the optical pulse. The cross-correlation technique has been applied to the measurement of electron bunches in FELIX, showing single bunches of around 500fs FWHM. The resolution is limited primarily by the electro-optic crystal thickness and the relatively low energy of the electrons (50 MeV).  
 
THPLT113 Conceptual Design of a Microwave Confocal Resonator Pick-up pick-up, impedance, damping, extraction 2750
 
  • V.G. Ziemann, A. Ferrari, T. Lofnes
    TSL, Uppsala
  • F. Caspers, I. Syratchev
    CERN, Geneva
  A confocal resonator may be used as a pick-up for frequencies in the multi-GHz region. In this report we discuss the design by analytical and numerical methods of such a device. Furthermore we discuss engineering issues such as the damping of unwanted modes, shielding of image fields and manufacturing tolerances. Such a device can be used both as pick-up and kicker where the actual structure is several wavelengths away from the beam in the transverse direction. It is intended for highly relativistic beams and does not require changing particle trajectory as opposed to a diagnostic wiggler.  
 
THPLT123 Coupling Coefficients in the Inhomogeneous Cavity Chain electromagnetic-fields, damping, acceleration 2759
 
  • K. Kramarenko, M.I. Ayzatskiy
    NSC/KIPT, Kharkov
  In this paper a mathematical method on the base of a rigorous electrodynamic approach for description of inhomogeneous chain of cylindrical cavities is presented. The form of the obtained for chosen amplitudes set of equations is similar to the set of equations that describe the simple coupled circuit chain. As the cavity have the infinite number of resonant frequencies, to obtain the coupling coefficients one have to solve additional infinite set of linear equations with coefficients that depend on the frequency. Using the developed method in the case of inhomogeneous cavity chain we calculated the dependence of the coupling coefficients on frequency and geometrical sizes with taking into account the 'long-range' coupling.  
 
THPLT150 Results from Orbit and Optics Improvement by Evaluating the Nonlinear Beam Position Monitor Response in CESR betatron, closed-orbit, optics, electron 2807
 
  • R.W. Helms, G. Hoffstaetter
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  In the Cornell Electron/positron Storage Ring (CESR), pretzel orbits with large horizontal oscillations are used to keep electron and positron beams out of collision except at the interaction point. Since a beam position monitor's (BPM's) response is only linear near the center of the beam pipe, the assumption of linearity does not allow for accurate orbit and phase measurements under colliding beam conditions. Using a numerical model of the BPMs' response to large offsets of the beam position, and an enhanced algorithm for real-time inversion of this nonlinear response function, we have extended our orbit and betatron phase measurements to beams with large pretzel amplitudes. Several measurements demonstrate the applicability, accuracy, and usefulness of this method.  
 
THPLT151 Evaluation of Beam Position Monitors in the Nonlinear Regime betatron, closed-orbit, electron, positron 2810
 
  • R.W. Helms, G. Hoffstaetter
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Here we present a new algorithm for processing BPM signals and extracting orbit and phase data for very large beam excursion where the BPM response function changes nonlinearly with the beam position. Using two dimensional models of each BPM geometry, we calculate the button response using numerical solution of Laplace's equation and Green's reciprocity theorem. The difference between the calculated signals and the measured signals is minimized in real time to calculate the beam position and measurement errors. Using the derivatives of the response functions, we model the effect of beam shaking, and from it, calculate the betatron phase.  
 
THPLT162 Diagnosis of Coupling and Beta Function Errors in the PEP-II B-Factory betatron, lattice, storage-ring, resonance 2840
 
  • M.H. Donald, T.M. Himel, S. Zelazny
    SLAC, Menlo Park, California
  The SLAC Control program has an automatic phase measuring system whereby the beta functions of the two storage rings are measured. This facility has recently been extended to measure coupling between the horizontal and vertical motion and to fit the measured values to their modes of propagation. This facility aids the diagnosis and correction of coupling and focusing errors.  
 
THPLT170 Finding the Circular Magnet Aperture which Encloses an Arbitrary Number of Midplane-centered Beam Ellipses closed-orbit, superconducting-magnet, lattice 2858
 
  • J.S. Berg
    BNL, Upton, Long Island, New York
  In specifying the magnets for an accelerator, one must be able to determine the aperture required by the beam. In some machines, in particular FFAGs, there is a significant variation in the closed orbit and beta functions over the energy range of the machine. In addition, the closed orbit and beta functions may vary with the longitudinal position in the magnet. It is necessary to determine a magnet aperture which encloses the beam ellipses at all energies and all positions in the magnet. This paper describes a method of determining the smallest circular aperture enclosing an arbitrary number of midplane-centered ellipses.