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kicker

  
Paper Title Other Keywords Page
MOPCH074 Layout of an Accumulator and Decelerator Ring for FAIR antiproton, pick-up, injection, electron 199
 
  • P. Beller, K. Beckert, C. Dimopoulou, A. Dolinskii, F. Nolden, M. Steck, J. Yang
    GSI, Darmstadt
  Antiproton physics and experiments with rare isotope beams are major research fields at FAIR. Antiproton physics requires the accumulation of high intensity antiproton beams. The accumulation of up to 1011 antiprotons at 3 GeV is foreseen. This will be accomplished by the combination of the collector ring CR for stochastic precooling and the specialized accumulator ring RESR. The accumulation scheme in the RESR is based on the usage of a stochastic cooling system. The requirements of this cooling system strongly affect the magnetic structure of the RESR. For experiments with short-lived rare isotope beams the RESR serves the task of fast deceleration. Precooled rare isotope beams will be injected at 740 MeV/u and then decelerated to energies between 100 and 400 MeV/u in less than 1 s. This contribution presents the ring design and lattice studies relevant for both tasks of the ring as well as a description of the antiproton accumulation scheme.  
 
MOPCH077 The Collector Ring CR of the FAIR Project antiproton, pick-up, injection, extraction 208
 
  • F. Nolden, K. Beckert, P. Beller, U. Blell, C. Dimopoulou, A. Dolinskii, U. Laier, G. Moritz, C. Muehle, I. Nesmiyan, C. Peschke, M. Steck
    GSI, Darmstadt
  The Collector Ring is a storage ring in the framework of the FAIR project. It has the purpose of stochastic precooling of both rare isotope and antiproton beams and of measurung nuclear masses in an isochronous setting. The paper discusses progress in the development of magnet systems, rf systems, injection/extraction strategies and stochastic cooling systems. Finally it is discussed how to confirm the predicted performance of the slotline electrodes developed recently for stochastic cooling.  
 
MOPCH085 Pickup Structures for the HESR Stochastic Cooling System pick-up, COSY, vacuum, ion 228
 
  • R. Stassen, P.B. Brittner, G. Schug, H.S. Singer
    FZJ, Jülich
  The design of the High-Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt includes electron and stochastic cooling. Simulations have shown that the bandwidth of a 2-4 GHz stochastic cooling system is sufficient to achieve the requested beam parameter at the internal target. New 2-4 GHz pickup structures have been developed and tested. First results of the low impedance, printed loop structures will be presented.  
 
MOPCH086 Stochastic Cooling for the HESR at the GSI-FAIR Complex target, antiproton, emittance, pick-up 231
 
  • H. Stockhorst, B. Lorentz, R. Maier, D. Prasuhn
    FZJ, Jülich
  • T. Katayama
    CNS, Saitama
  The High-Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt is planned as an anti-proton cooler ring in the momentum range from 1.5 to 15 GeV/c. An important and challenging feature of the new facility is the combi-nation of phase space cooled beams with internal targets. The required beam parameters and intensities are prepared in two operation modes: the high luminosity mode with beam intensities up to 1011 and the high reso-lution mode with 1010 anti-protons cooled down to a relative momentum spread of only a few 10-5. In addition to electron cooling, transverse and longitudinal stochastic cooling are envisaged to accomplish these goals. It is shown how the great benefit of the stochastic cooling system to adjust the cooling force in all phase planes independently is utilized to achieve the requested beam spot and the high momentum resolution at the internal target within reasonable cooling down times for both HESR modes even in the presence of intra-beam scattering. A numerical and analytical approach to the Fokker-Planck equation for longitudinal filter cooling has been carried out.  
 
MOPCH109 Design Studies on a Novel Stellarator Type High Current Ion Storage Ring ion, injection, plasma, space-charge 297
 
  • M. Droba, N.S. Joshi, O. Meusel, P. Nonn, U. Ratzinger
    IAP, Frankfurt-am-Main
  A high current storage ring for the accumulation of ion beams provided by a new 150 kV terminal is under consideration at the Frankfurt University. The configuration based on a toroidal magnetic field seems promising for the storage of intense low energy ion beams, especially when concerning the various potential concepts for space charge compensation. The theory of plasma confinement on magnetic surface is transformed to numerical simulations on circulating ion beams. The space charge effects and stability conditions are studied and will be presented. Various injection techniques based on crossed field-drifts are investigated. Accordingly test experiments are prepared based on two 30 degree toroidal sectors at a major radius of 1.3m with a maximum toroidal magnetic field of 0.6T on axis.  
 
MOPCH129 Status of the SNS Beam Power Upgrade Project SNS, target, linac, emittance 345
 
  • S. Henderson, A.V. Aleksandrov, D.E. Anderson, S. Assadi, I.E. Campisi, F. Casagrande, M.S. Champion, R.I. Cutler, V.V. Danilov, G.W. Dodson, D.A. Everitt, J. Galambos, J.R. Haines, J.A. Holmes, N. Holtkamp, T. Hunter, D.-O. Jeon, S.-H. Kim, D.C. Lousteau, T.L. Mann, M.P. McCarthy, T. McManamy, G.R. Murdoch, M.A. Plum, B.R. Riemer, M.P. Stockli, D. Stout, R.F. Welton
    ORNL, Oak Ridge, Tennessee
  The baseline Spallation Neutron Source (SNS) accelerator complex, consisting of an H- injector, a 1 GeV linear accelerator, an accumulator ring and associated transport lines, will provide a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron production. Upgrades to the SNS accelerator and target systems to increase the beam power to at least 2 MW, with a design goal of 3 MW, are in the planning stages. The increased SNS beam power can be achieved primarily by increasing the peak H- ion source current from 38 mA to 59 mA, installing additional superconducting cryomodules to increase the final linac beam energy to 1.3 GeV, and modifying injection and extraction hardware in the ring to handle the increased beam energy. The mercury target power handling capability will be increased to 2 MW or greater by i) mitigating cavitation damage to the target container through improved materials/surface treatments, and introducing a fine dispersion of gas bubbles in the mercury, and ii) upgrading the proton beam window, inner reflector plug and moderators. The upgrade beam parameters will be presented and the required hardware modifications will be described.  
 
MOPLS033 Beam-beam Limit and Feedback Noise feedback, damping, luminosity, radiation 619
 
  • K. Ohmi, Y. Funakoshi, S. Hiramatsu, K. Oide, M. Tobiyama
    KEK, Ibaraki
  Beam-beam interaction is strongly nonlinear, therefore particles in the beam experience chaotic motion. A small noise can be enhanced by the chaotic nature, with the result that unexpected emittance growth can be observed. We study the noise of transverse bunch by bunch feedback system and related luminosity degradation. Similar effects caused by crab cavity noise is also discussed.  
 
MOPLS088 Resonant Kicker System for Head-on-collision Option of Linear Collider electron, positron, linear-collider, collider 759
 
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto
  The separation of incoming and outgoing (electron and positron) beams at the interaction point of a linear collider is investigated using a resonant kicker system. It should enable head-on-collisions at the interaction point with the use of staggered passing times for each bunch at certain locations. Magnetic core materials for such a resonant kicker with a frequency of 6MHz are under investigation. Such a kicker system should minimize the perturbation of the incoming bunch with a finite bunch length, while it kicks the outgoing bunch by more than 1 millirad. Various arrangements of such kickers along the beamlines are discussed.  
 
MOPLS090 Design of a Strip-line Extraction Kicker for CTF3 Combiner Ring impedance, simulation, CTF3, power-supply 762
 
  • I. Rodriguez, F. Toral
    CIEMAT, Madrid
  • L. García-Tabarés
    CEDEX, Madrid
  • A. Ghigo, F. Marcellini
    INFN/LNF, Frascati (Roma)
  The new CLIC test facility (CTF3) is the latest stage to prove the technical feasibility of the CLIC project. An extraction kicker is necessary for the combiner ring, and it will be a strip-line type device due to lower coupling impedances and straightforward fabrication. The field uniformity together with a correct beam dynamics are the most challenging issues of this design. The main parameters of the kicker are analytically calculated using standard analytic formulae. The numeric modelling and simulation of several possible straight sections are reported, and the characteristic impedance is matched with the 50 Ω load. The field homogeneity, the kick angle and the scattering parameters are calculated in a 3D finite element model. Several manufacturing issues for the first prototype are also outlined.  
 
MOPLS092 Efficient Collimation and Machine Protection for the Compact Linear Collider CLIC, collimation, linac, luminosity 768
 
  • R.W. Assmann, F. Zimmermann
    CERN, Geneva
  We present a new approach to machine protection and collimation in CLIC, separating these two functions: If emergency dumps in the linac protect the downstream beam line against drive-beam failures, the energy collimation only needs to clean the beam tails and can be compact. Overall, the length of the beam delivery system is significantly reduced.  
 
MOPLS106 Independent Operation of Electron/Positron Wings of ILC positron, electron, target, linac 810
 
  • A.A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  We represent a concept of fast feedback system allowing independent operation of electron-positron wings of ILC.  
 
MOPLS122 Design of the ILC Prototype FONT4 Digital Intra-train Beam-based Feedback System feedback, extraction, linear-collider, KEK 849
 
  • P. Burrows
    Queen Mary University of London, London
  • G.B. Christian, H. Dabiri Khah, A.F. Hartin, G.R. White
    JAI, Oxford
  • C.C. Clarke, C. Perry
    OXFORDphysics, Oxford, Oxon
  • A. Kalinin
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • D.J. McCormick, S. Molloy, M.C. Ross
    SLAC, Menlo Park, California
  We report on the design and initial testing of the 4th generation Feedback on Nanosecond Timescales (FONT) prototype intra-train beam-based feedback system for beam control and luminosity optimisation at the International Linear Collider (ILC). FONT4 comprises a fast-analogue front-end BPM signal processor, with an FPGA-based digital feedback processor and a fast-risetime kicker-driver amplifier. The system is being designed with a total latency budget (including signal propagation delays) of about 140ns. FONT4 will be deployed at the Accelerator Test Facility (ATF) at KEK, where it will be tested with the electron bunchtrain extracted from the ATF damping ring. The bunches will have a spacing of c. 150ns, chosen to match the ILC design. We report the results of initial beam tests of the system components. We aim to demonstrate feedback, with delay-loop operation, on this ILC-like bunchtrain.  
 
MOPLS123 Performance of the FONT3 Fast Analogue Intra-train Beam-based Feedback System at ATF feedback, linear-collider, SLAC, CLIC 852
 
  • P. Burrows
    Queen Mary University of London, London
  • G.B. Christian, A.F. Hartin, H.D. Khah, G.R. White
    JAI, Oxford
  • C.C. Clarke, C. Perry
    OXFORDphysics, Oxford, Oxon
  • A. Kalinin
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • D.J. McCormick, S. Molloy, M.C. Ross
    SLAC, Menlo Park, California
  We report on the design and testing of the 3rd generation Feedback On Nanosecond Timescales (FONT) prototype intra-train beam-based feedback system for beam control and luminosity optimisation at the International Linear Collider (ILC). The all-analogue FONT3 electronics was designed to have an ultra-short latency of c. 10ns. We describe the design of the BPM signal processor, feedback circuit and kicker-driver amplifier. We report on deployment of FONT3 at the Accelerator Test Facility (ATF) at KEK, where it was tested with the 56ns-long electron bunchtrain extracted from the ATF damping ring. Feedback, with delay-loop operation, on the beam was demonstrated with a latency close to design. We comment on the applicability of this technology to ILC, as well as future warm-RF based linear colliders, such as CLIC.  
 
MOPLS139 Choosing a Baseline Configuration for the ILC Damping Rings damping, lattice, wiggler, dynamic-aperture 885
 
  • A. Wolski
    Liverpool University, Science Faculty, Liverpool
  • J. Gao
    IHEP Beijing, Beijing
  • S. Guiducci
    INFN/LNF, Frascati (Roma)
  The damping rings for the International Linear Collider must be capable of accepting large beams from the electron and positron sources, and producing highly damped beams meeting demanding stability specifications, at the machine repetition rate of 5 Hz. Between March and November 2005, a program of studies was undertaken by an international collaboration of 50 researchers to compare a number of configuration options, including ring circumferences between 3 and 17 km. Here, we outline the studies and discuss the principal considerations in the choices of the baseline and alternative damping ring configurations.  
 
TUOBFI01 A Diagnostic Kicker System as a Versatile Tool for Storage Ring Characterisations diagnostics, storage-ring, controls, synchrotron 974
 
  • O. Dressler, J. Feikes, J. Kolbe
    BESSY GmbH, Berlin
  For the BESSY II Synchrotron Light Source two diagnostic kicker systems including current pulsers were developed, allowing vertical and horizontal deflection of the stored beam. Synchronised with the revolution trigger, simultaneous pulsing of the systems kicks the stored beam in any transverse direction with a repetition rate of up to 10 Hz allowing a wide range of storage ring investigations. Examples are dynamic aperture measurements and frequency map measurements. Special efforts were made to assure the demands of high amplitude and time stability for this kind of experiments. The technical concept of the systems and the controlling of the measurements are described.  
slides icon Transparencies
 
TUPCH003 Diagnostics and Timing at the Australian Synchrotron diagnostics, storage-ring, injection, synchrotron 995
 
  • M.J. Spencer, S. Banks, M.J. Boland, M. Clift, R.T. Dowd, R. Farnsworth, S. Hunt, G. LeBlanc, M. Mallis, B. Mountford, Y.E. Tan, A. Walsh, K. Zingre
    ASP, Clayton, Victoria
  The 3GeV Australian Synchrotron will begin operation in March 2007. This paper outlines the storage ring diagnostics systems and the injection timing system. The diagnostics system includes an optical beamline with streak camera, an x-ray beamline with pinhole array, a diagnostic straight with fast feedback kicker, stripline, direct current current transformer, and a four-fingered scraper. Over the 14 sectors there are 98 beam position monitors and 14 movable beam loss monitors. The timing system is based on a static injection system with the storage ring bucket to be filled targeted by delaying the firing of the electron gun.  
 
TUPCH052 Turn by Turn Measurements at DAFNE Based on the Libera Beam Position Processor betatron, pick-up, injection, controls 1124
 
  • A. Stella, M. Serio
    INFN/LNF, Frascati (Roma)
  The BPM detection electronics developed by Instrumentation Techonologies implements digital receivers technology to measure beam position from the amplitude of pick-up signals. Besides the closed orbit mode, the Libera module can be operated also in the Turn-by-Turn mode. Operational experience with Libera at DAFNE, the Frascati e+ e- collider, has been focused on this functionality. Data obtained from DAFNE have been processed with well established extraction algorithms to accurately measure the betatron tunes from a small number of turns, providing instantaneous information on tune variations occurred also in fast damped decays after a kick. Hardware and software implementation together with experimental data are reported.  
 
TUPLS001 Enhanced Optical Cooling of Ion Beams for LHC ion, undulator, betatron, pick-up 1483
 
  • E.G. Bessonov, M.V. Gorbunkov
    LPI, Moscow
  • A.A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  Enhanced optical cooling (EOC) of fully stripped lead ions in LHC is investigated. The method of EOC is based on the usage of pickup and kicker undulators and optical amplifier. External selectivity is arranged by a moving screen located on the image plane of the optical system, projecting the emitted undulator radiation there (see physics/0509196). Nonlinear features of cooling and requirements to the ring lattice, optical and laser systems are discussed. Comparison with classical optical stochastic cooling (OSC) is represented as well.  
 
TUPLS009 Design and Tests of New Fast Kickers for the DAFNE Collider and the ILC Damping Rings impedance, injection, damping, positron 1502
 
  • D. Alesini, S. Guiducci, F. Marcellini, P. Raimondi
    INFN/LNF, Frascati (Roma)
  In this paper we illustrate the design of new, fast stripline kickers to inject or extract bunches in electron/positron rings. The kickers have been designed for the injection upgrade of the Phi-factory DAFNE and as injection/extraction devices for the International Linear Collider (ILC) damping rings. The design is based on tapering the striplines in order to simultaneously obtain low impedance and an excellent uniformity of the deflecting field. The design has been done using 2D and 3D electromagnetic codes such as Superfish and HFSS. High voltage test results on prototypes are also shown.  
 
TUPLS011 The Beam Screen for the LHC Injection Kicker Magnets impedance, LHC, injection, vacuum 1508
 
  • M.J. Barnes, F. Caspers, L. Ducimetière, N. Garrel, T. Kroyer
    CERN, Geneva
  The two LHC injection kicker magnet systems must each produce a kick of 1.2 T.m with a flattop duration variable up to 7.86 μs, and rise and fall times of less than 0.9 μs and 3 μs, respectively. Each system is composed of four 5 Ω transmission line kicker magnets with matched terminating resistors and pulse forming networks (PFN). The LHC beam has a high intensity, hence a beam screen is required in the aperture of the magnets This screen consists of a ceramic tube with conducting "stripes" on the inner wall. The stripes provide a path for the image current of the beam and screen the magnet ferrites against Wake fields. The stripes initially used gave adequately low beam impedance however stripe discharges occured during pulsing of the magnet: hence further development of the beam screen was undertaken. This paper presents options considered to meet the often conflicting needs for low beam impedance, shielding of the ferrite, fast field rise time and good electrical and vacuum behaviour.  
 
TUPLS013 Protection of the LHC against Unsynchronised Beam Aborts LHC, extraction, collimation, monitoring 1514
 
  • B. Goddard, R.W. Assmann, E. Carlier, J.A. Uythoven, J. Wenninger, W.J.M. Weterings
    CERN, Geneva
  An unsynchronised beam abort in the LHC could cause major damage to other downstream accelerator components, in particular the extraction septum magnets, the experimental low-beta triplet magnet apertures and the tertiary collimators. Although the LHC beam dumping system includes design features to minimise their frequency, such unsynchronised aborts can arise from several sources and cannot be excluded. A system of protection devices comprising fixed and moveable passive diluters and collimators will be built to safely protect the downstream LHC aperture from the mis-directed bunches in case of such a failure. The sources of unsynchronised abort events are described, together with the requirements and design of the protection devices and their expected performance. The accompanying operational requirements and envisaged solutions are discussed, in particular the problem of ensuring the local orbit at the protection devices.  
 
TUPLS015 Calibration Measurements of the LHC Beam Dumping System Extraction Kicker Magnets LHC, extraction, dumping, CERN 1520
 
  • J.A. Uythoven, F. Castronuovo, L. Ducimetière, B. Goddard, G. Gräwer, F. Olivieri, L. Pereira, E. Vossenberg
    CERN, Geneva
  The LHC beam dumping system must protect the LHC machine from damage by reliably and safely extracting and absorbing the circulating beams when requested. Two sets of 15 extraction kicker magnets form the main active part of this system. They have been produced, tested and calibrated by measuring the integrated magnetic field and the magnet current at different beam energies. The calibration data have been analysed, and the critical parameters are compared with the specifications. Implications for the configuration, control and operation of the beam dumping system are discussed.  
 
TUPLS076 Beam Extraction of 150 MeV FFAG extraction, septum, power-supply, KEK 1672
 
  • M. Aiba, Y. Mori, H. Nakayama, K. Okabe, Y. Sakamoto, A. Takagi
    KEK, Ibaraki
  • R. Taki
    GUAS/AS, Ibaraki
  • Y. Yonemura
    Kyushu University, Fukuoka
  A beam extraction from FFAG accelerator was performed for the first time at KEK 150MeV proton FFAG synchrotron. The purpose of 150MeV FFAG project is to establish a working prototype for various applications. The beam extraction is thus one of important goals. The extraction is based on fast extraction methode using kicker and pulse septum working at 100Hz. A rapid cycling is also our focus to take advantages of FFAG accelerator. Beam extraction experiment was successful under 100Hz operating. The details of experiment will be presented in this paper.  
 
TUPLS079 Hadron Cancer Therapy Complex Employing Non-scaling FFAG Accelerator and Fixed Field Gantry Design acceleration, extraction, proton, resonance 1681
 
  • E. Keil
    CERN, Geneva
  • A. Sessler
    LBNL, Berkeley, California
  • D. Trbojevic
    BNL, Upton, Long Island, New York
  Non-scaling FFAG rings for cancer hadron therapy offer reduced physical aperture and large dynamic aperture as compared with scaling FFAGs. The variation of tune with energy implies the crossing of resonances during acceleration. Our design avoids intrinsic resonances, although imperfection resonances must still be crossed. We consider a system of three non-scaling FFAG rings for cancer therapy with 250 MeV protons and 400 MeV/u carbon ions. Hadrons are accelerated in a common RFQ and linear accelerator, and injected into the FFAG rings at v/c=0.1128. The H+/C6+ ions are accelerated in the two smaller/larger rings to 31 and 250 MeV/52.5 and 400 MeV/u kinetic energy, respectively. The lattices consist of symmetrical triplet cells with a straight section for RF cavities. The gantry with similar triplet cells accepts the whole required momentum range at fixed field. This unique design uses either High Temperature super-conductors or super-conducting magnets reducing gantry size and weight. Elements with a variable field at the beginning and at the end set the extracted beam at the correct position for the specific energy and adapt the beam to specific requirements during treatment.  
 
TUPLS110 Measurement of the Extraction Kicker System in J-PARC RCS vacuum, extraction, LEFT, proton 1759
 
  • J. Kamiya, M. Kinsho, M. Kuramochi, T. Takayanagi, O. Takeda, T. Ueno, M. Watanabe, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  Kicker magnet system in the J-PARC RCS is now under construction at JAEA (Japan Atomic Energy Agency). Their role in RCS is to kick the accelerated 3 GeV proton beam to the following extraction line at a repetition rate of 25 Hz. There are three kinds of kicker magnets (S, M, L), distinguished by the difference in the size of their apertures. The specification of 2 % is required on the magnetic field in terms of homogeneity in time and space from the beam optical point of view. The required flatness of the temporal uniformity was accomplished by superposing the waveforms of the two kicker magnet*. The required specification to the special uniformity is also very severe to achieve because our kicker magnet is designed with a large aperture in order to accept a maximum beam power of 1 MW. We established the search coil as a detector and 3-axes stage to perform magnetic field mapping. In order to reduce the signal noises and detect the stable output signals, matching register and integrated circuit were carefully selected. The 3-axes stage was precisely aligned. The distribution of the magnetic field (By) and integrated BL were systematically measured for the three types of kickers.

*J. Kamiya et al. “Magnetic field measurement of the extraction kicker magnet in J-PARC RCS,” submitted for publication to the proceedings of the 19th International Conference on Magnet Technology.

 
 
TUPLS114 An Improvement of Matching Circuit of RF Kicker Electrodes extraction, controls, feedback, impedance 1771
 
  • T. Kurita, S. Fukumoto, S.H. Hatori
    WERC, Tsuruga , Fukui
  • S. Ninomiya
    KEK, Ibaraki
  Beam extraction system at accelerator of The Wakasa Wan Energy Research Center employs RF knockout technology. Narrow band RF noise is applied to the transverse kicker electrodes to increase betatron amplitude of the beam. Recently some improvements of the beam extraction system are introduced: To improve the shape of the spill, a feedback control of noise amplitude is introduced. The feedback control system works as an attenuator, therefore it is necessary to enhance the noise amplitude of the kicker electrodes to obtain agreeable effect on the spill shape. In order to obtain a higher voltage, we revamp the matching circuit at the electrodes. By introducing the resonating characteristic at the matching circuit, we obtained 3 times more amplitude at the electrodes. General shape of the spill is improved by this work, and extraction efficiency at a real operating condition is also improved.  
 
TUPLS116 Extraction System Design for the CSNS/RCS extraction, septum, shielding, lattice 1777
 
  • J. Tang, Y. Chen, Y.L. Chi, Y.L. Jiang, W. Kang, J.B. Pang, Q. Qin, S. Wang, W. Wang
    IHEP Beijing, Beijing
  • J. Wei
    BNL, Upton, Long Island, New York
  The CSNS extraction system takes use one of the four dispersion-free straight sections. Five vertical kickers and one Lambertson septum magnet are used for the one-turn extraction. The rise time of less 250 ns and the total kicking angle of 20 mrad are required for the kickers that are grouped into two tanks. The design for the kicker magnets and the PFN is also given. To reduce the low beam loss in the extraction channels due to large halo emittance, large apertures are used for both the kickers and septum. Stray magnetic field inside and at the two ends of the circulating path of the Lambertson magnet and its effect to the beam has been studied.  
 
TUPLS122 Implementation of the Proposed Multiturn Extraction at the CERN Proton Synchrotron extraction, septum, beam-losses, SPS 1789
 
  • M. Giovannozzi
    CERN, Geneva
  Following the positive results of the three-year measurement campaign at the CERN Proton Synchrotron concerning beam splitting with stable islands in the transverse phase space, the study of a possible implementation of the proposed multi-turn extraction was undertaken. The novel approach would allow a substantial reduction of beam losses, with respect to the present scheme, when delivering the high-intensity proton beams required for the planned CERN Neutrino to Gran Sasso Project. Major modifications to the ring layout are foreseen, such as a new design of the extraction bumps including also the installation of three additional kickers to create a closed-bump over the five turns used to extract the split beam. The ring aperture was reviewed and improvements are proposed to reduce possible beam losses between beam splitting and extraction. The goal consists of implementing the proposed changes by the end of the 2007/2008 PS shutdown and to commission the novel extraction during the 2008 physics run.  
 
TUPLS123 Design of the LHC Beam Dump Entrance Window LHC, vacuum, CERN, proton 1792
 
  • R. Veness, B. Goddard, S.J. Mathot, A. Presland
    CERN, Geneva
  • L. Massidda
    CRS4, PULA
  7 TeV proton beams from the LHC are ejected through a 600 m long beam dump transfer line vacuum chamber to a beam dump block. The dump block is contained within an inert gas-filled vessel to prevent a possible fire risk. The dump vessel and transfer line are separated by a 600 mm diameter window, which must withstand both the static pressure load and thermal shock from the passage of the LHC beam. In a previous paper* the functional requirements and conceptual design of this window were outlined. This paper describes the analysis leading to the final design of the window. The choice of materials is explained and tests performed on the prototype window are summarized.

*A. Presland et al. "A large diameter entrance window for the LHC beam dump line". Proc. PAC 2005, 1698-1700.

 
 
WEYPA02 Damping Rings towards Ultra-low Emittances damping, wiggler, emittance, electron 1857
 
  • S. Guiducci
    INFN/LNF, Frascati (Roma)
  The presentation will review the various designs of Damping Rings to achieve ultra-low emittance beams in Linear Colliders (ILC and CLIC) pointing out the major issues both from the beam dynamics and the technological point of vue and comparing the required performances with the one achieved in SLC or FFTB. It will then present the design, beam simulations, benchmarking and performances already achieved in test facilities, especially the ATF1 facility developed and operated at KEK. Finally, it will present future R&D plans and schedule in terms of beam performances, beam stability and technological development as well as the world-wide organization to achieve them.  
slides icon Transparencies
 
WEPCH029 Injection and Extraction Orbit of the J-PARC Main Ring extraction, injection, beam-losses, quadrupole 1987
 
  • M. Tomizawa, Y. Kamiya, H. Kobayashi, I. Sakai, Y. Shirakabe
    KEK, Ibaraki
  • S. Machida
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  The J-PARC main ring (MR) accelerates a high intensity proton beam and deliver to the neutrino experimental hall by the fast extraction and to the hadron experimental facility by the slow extraction. The beam from the rapid cycle synchrotron (RCS) is injected by the bunch to bucket transfer into the MR. The MR has two beam dump lines, the first one is used to dump the beam at injection energy and the second one can be used to abort accelerated beam. The beam loss at the injection and extraction is one of the critical issue for high intensity proton accelerators. We report designed injection and extraction orbits and discuss about the beam apertures and the beam loss.  
 
WEPCH032 Orbit Correction System for S-LSR Dispersion-free Mode proton, closed-orbit, electron, ion 1993
 
  • H. Souda, S. Fujimoto, M. Ikegami, A. Noda, T. Shirai, M. Tanabe
    Kyoto ICR, Uji, Kyoto
  • H. Fadil
    MPI-K, Heidelberg
  An ion storage ring S-LSR has been constructed at ICR, Kyoto Univ. It is a small ring with 22.557m circumference, and has an electron cooler and laser cooling section to achieve crystalline beam. In the commissioning process, closed orbit correction of a 7MeV proton beam has been successfully realized by means of Simplex Method. Responses to the correctors are linear only within narrow limits because of the space-charge effect in the electron cooler. Therefore, the correction must be repetition of small corrections. Under such condition, measured COD has been reduced less than 0.1mm. Orbit correction is necessary for 35keV Mg+ dispersion-free mode* using both bending magnets and electrostatic deflectors. Since electrostatic deflectors have relatively large field errors, it needs a special process to inject the beam into the dispersion-free mode ring. First circulation is under only the magnetic field, then, the electric field will be added little by little applying continuous COD correction. In this way the dispersion gradually diminishes with keeping stable orbit. In this paper we present the correction scheme and the trial to the dispersion-free circulation.

*M. Ikegami et al. Phys. Rev. ST-AB, 7, 120101-1 (2004).

 
 
WEPCH055 A New Algorithm for the Correction of the Linear Coupling at TEVATRON coupling, optics, controls, quadrupole 2047
 
  • Y. Alexahin, E. Gianfelice-Wendt
    Fermilab, Batavia, Illinois
  The Fourier analysis of TBT data provides valuable information about the machine linear and non-linear optics. The recent upgrade of the Beam Position Monitors system made it possible to exploit this technique also at Tevatron. A program for the measurement and correction of the linear coupling based on this approach has been integrated in the TEVATRON control system. With respect to the method based on the empirical adjustment of the strength of the skew quadrupoles, the new method has the advantage of being faster and of allowing the measurement of the coupling also during the acceleration. Moreover it offers also information about the sum coupling coefficient and about the location of the sources of coupling.  
 
WEPCH057 Measurement and Optimization of the Lattice Functions in the Debuncher Ring at Fermilab lattice, optics, antiproton, injection 2050
 
  • V.P. Nagaslaev, K. Gollwitzer, V.A. Lebedev, A. Valishev
    Fermilab, Batavia, Illinois
  • V. Sajaev
    ANL, Argonne, Illinois
  A goal of the Tevatron Run-II upgrade requires substantial increase of antiproton production. The central step towards this goal is increasing the Debuncher ring admittance. Detailed understanding of the Debuncher's optics, aperture limitations and lattice functions is necessary. The method of the response matrix optimization has been used to determine quadrupole errors and corrections to the design functions. The measurement accuracy is about 5% due to the Beam Position Monitor system resolution and the small number of steering elements in the machine. We have used these accurate measurements to redesign the machine optics to maximize the acceptance of the Debuncher where the main limiting apertures are the stochastic cooling pickups and kickers. Accuracy of the measurements and the limitations are discussed as well as details of the optics modification.  
 
WEPCH113 Numerical Impedance Calculations for the GSI SIS-100/300 Kickers impedance, coupling, injection, simulation 2179
 
  • B. Doliwa, H. De Gersem, T. Weiland
    TEMF, Darmstadt
  Fast kicker modules represent a potential source for beam instabilities in the planned Facility for Antiproton and Ion Research (FAIR) at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt. In particular, the more than fifty kicker modules to be installed in the SIS-100 and SIS-300 synchrotrons are expected to have a considerable parasitic influence on the high-current beam dynamics. Here we present our numerical investigations of the longitudinal and transverse kicker coupling impedances using a specialized electromagnetic field software. Besides the coupling to the external network, particular attention is paid to the question whether a resistively-coated ceramic beam pipe is able to reduce coupling impedances and ferrite heating significantly.  
 
WEPLS115 Impedances in Slotted-Pipe Kicker Magnets impedance, vacuum, storage-ring, simulation 2649
 
  • F. Marhauser, O. Dressler, V. Duerr, J. Feikes
    BESSY GmbH, Berlin
  Storage ring slotted-pipe kicker magnets based on the DELTA design are foreseen for the Metrology Light Source (MLS) of the Physikalisch-Technische Bundesanstalt currently under construction near the BESSY site. Although the slotted pipe maintains the cross-section of the storage ring vacuum chamber, image currents have to bypass the slots generating wakefields. Actually modes with substantial impedances have been revealed by simulations and verified by measurements of a kicker model for the MLS.  
 
WEPLS140 Update and Summary of the Dependability Assessment of the LHC Beam Dumping System LHC, dumping, beam-losses, CERN 2706
 
  • R. Filippini, J.A. Uythoven
    CERN, Geneva
  The LHC Beam Dumping System (LBDS) must be able to remove the high intensity beams from the LHC accelerator on demand, at any moment during the operation. As the consequences of a major failure can be very severe, stringent safety requirements were imposed on the design. The final results of an in-depth dependability analysis on the LBDS are summarised, for one year of operation and different operational scenarios. The trade-off between safety and availability is discussed, along with the benefit from built-in features like redundancy, on-line surveillance and post-mortem diagnostics.  
 
THPCH045 Transverse Head-tail Modes Elimination with Negative Chromaticity and the Transverse Multi-bunch Feedback System at ELETTRA feedback, ELETTRA, impedance, coupling 2886
 
  • E. Karantzoulis, M. Lonza
    ELETTRA, Basovizza, Trieste
  The rigid dipole head-tail mode threshold at ELETTRA is by now quite low and increasing positively the chromaticity does not bring a much overall advantage in the machine performance. Using the bunch-by-bunch transverse feedback (TMFB), a threshold increase has been observed until the onset of the higher modes, which being bunch shape modes cannot be detected and therefore eliminated by the feedback system. To overcome this problem the machine has been set to a small but negative chromaticity. In this case the m=0 mode is unstable with a very low (<1 mA/bunch) threshold but the higher modes should be stable, especially when the main source of the transverse impedance comes from the resistive wall as in our case. Indeed when activating the TMFB no onset of any modes was observed within reasonable current limits (15 mA/bunch) that we plan to further investigate. In the paper after a theoretical discussion on the role of chromaticity and various types of impedances in the head-tail onset mechanism, the experimental results are presented and discussed.  
 
THPCH054 SIMPSONS with Wake Field Effects extraction, injection, impedance, emittance 2910
 
  • Y. Shobuda, F. Noda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • Y.H. Chin, K. Takata, T. Toyama
    KEK, Ibaraki
  • S. Machida
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  Simpsons, which is originally developed by S. Machida, is the program which calculates the space charge effect to the beam in the ring. The wake field effect to the beam is also installed in this program, because the emittance growth not only due to the space charge effect, but also due to the wake field effect is the important issue. The results of the simulation in J-PARC case are also represented.  
 
THPCH059 Kicker Impedance Measurements for the Future Multi-turn Extraction of the CERN Proton Synchrotron impedance, extraction, LEFT, resonance 2919
 
  • E. Métral, F. Caspers, M. Giovannozzi, A. Grudiev, T. Kroyer, L. Sermeus
    CERN, Geneva
  In the context of the novel multi-turn extraction, where charged particles are trapped into stable islands in transverse phase space, the ejection of five beamlets will be performed by means of a set of three new kickers. Before installing them into the machine, a measurement campaign has been launched to evaluate the impedance of such devices. Two measurement techniques were used to try to disentangle the driving and detuning impedances. The first consists in measuring the longitudinal impedance for different transverse offsets using a single displaced wire. The sum of the transverse driving and detuning impedances is then deduced applying Panofsky-Wenzel theorem. The second uses two wires excited in opposite phase and yields the driving transverse impedance only. Finally, the consequences on the beam dynamics are also analyzed.  
 
THPCH065 Suppression of Transverse Instability by a Digital Damper damping, impedance, space-charge, antiproton 2934
 
  • A.V. Burov, V.A. Lebedev
    Fermilab, Batavia, Illinois
  When a beam phase space density increases, it makes its motion intrinsically unstable. To suppress the instabilities, dampers are required. With a progress of digital technology, digital dampers are getting to be more and more preferable, compared with analog ones. Conversion of an analog signal into digital one is described by a linear operator with explicit time dependence. Thus, the analog-digital converter (ADC) does not preserve a signal frequency. Instead, a monochromatic input signal is transformed into a mixture of all possible frequencies, combining the input one with multiples of the sampling frequency. Stability analysis has to include a cross-talk between all these combined frequencies. In this paper, we are analyzing a problem of stability for beam transverse microwave oscillations in a presence of digital damper; the impedance and the space charge are taken into account. The developed formalism is applied for antiproton beam in the Recycler Ring at Fermilab.  
 
THPCH078 Successful Bunched-Beam Stochastic Cooling in RHIC RHIC, ion, pick-up, proton 2967
 
  • J.M. Brennan, M. Blaskiewicz, F. Severino
    BNL, Upton, Long Island, New York
  Stochastic Cooling of high energy and high frequency bunched beam has been demonstrated in RHIC at 100 GeV. Narrowing of the Schottky spectrum and shorting of the bunch length resulted from cooling the beam for 90 minutes. The purpose of the stochastic cooling is to counteract the fundamental limit of the luminosity lifetime of heavy ions in RHIC which is Intra-Beam Scattering. IBS drives transverse emittance growth and longitudinal de-bunching. The major components of the system have been tested with heavy ion and proton beams in previous runs in RHIC, demonstrating that the difficult challenges of high frequency bunched beam stochastic cooling can be overcome. The vexing problem of pollution of the Schottky spectrum by coherent components is solved with optimized filtering and high dynamic range low noise electronics. A set of 16 high-Q cavities is used to achieve adequate kicker voltage in the 5 to 8 GHz band. This technique exploits the bunched beam time structure to level the microwave power requirement and enables the use of solid state amplifiers to drive the kickers. Because RHIC did not operate with heavy ions in the FY06 run, the system was tested with specially prepared low intensity protons bunches of 2·109 particles.  
 
THPCH082 Broadband Bunch by Bunch Feedback for the ESRF using a Single High Resolution and Fast Sampling FPGA DSP feedback, damping, FIR, pick-up 2976
 
  • E. Plouviez, P. Arnoux, F. Epaud, J. Jacob, J.M. Koch, N. Michel, G.A. Naylor, J.-L. Revol, V. Serriere, D. Vial
    ESRF, Grenoble
  In order to increase the current in the ESRF storage ring we have developed a set of multibunch feedback systems aimed at fighting longitudinal and transverse coupled bunch instabilities. The longitudinal feedback (LFB) has been the first system installed and tested. It was designed using the scheme developed at SLAC, ALS and INFN Frascati: bunch by bunch processing of a beam phase error signal and correction using a low Q kicker driven by a QPSK modulator. However, we took advantage for this development of the latest available technology for the signal processing electronics with high resolution, high sampling rate ADC and DAC, and FPGA DSP, as well as for the FPGA programming environment. It allowed us to substantially reduce the complexity: the algorithm runs on a single processor, the kicker requires only 200W of RF power to control a 6GeV beam, and the implementation took only about one year. We will describe the main features of our LFB and present the results already achieved in the damping of instabilities driven by our RF cavity HOM. We will also report on the status of the transverse feedback, which is being built up using the same FPGA system as the longitudinal one.  
 
THPCH084 Control Path of Longitudinal Multibunch-feedback System at HERA-p controls, proton, feedback, FIR 2982
 
  • F.E. Eints, S. Choroba, M.G. Hoffmann, U. Hurdelbrink, P.M. Morozov, J. Randhahn, S. Ruzin, S. Simrock
    DESY, Hamburg
  A longitudinal broadband damper system to control coupled bunch instabilities has been developed and installed in the proton accelerator HERA-p at the DESY. The control system consists of a control path and a Fast Diagnostic System (FDS) for oscillation diagnostic. The control path consists of FPGA-based digital controller, vector modulator, 1kW power amplifier, kicker-cavity and beam. In the FDS, the bunch phase signals are sampled by a digital FPGA board with 14Bit ADC (controller) with a sampling frequency of 10.4MHz. Phase calculation for all bunches and offset correction will be done by FPGA software which includes a digital filter. The filter has to be able to deal with a slowly changing synchrotron frequency. Here we consider a filter design which treats each of maximum 220 bunches as an independent oscillator which has to be damped. More sophisticated mode filter algorithms may be required to get better noise performance. The FPGA-board output signal modulates a 104 MHz sine-wave. The resulting logitudinal correction kick signal is provided by the kicker-cavity. Beside the technical details we present first operational experience and the actual system performance.  
 
THPCH085 The Longitudinal Coupled Bunch Feedback for HERA-p feedback, diagnostics, luminosity, controls 2985
 
  • M.G. Hoffmann, S. Choroba, F.E. Eints, U. Hurdelbrink, P.M. Morozov, J. Randhahn, S. Ruzin, S. Simrock, E. Vogel, R. Wagner
    DESY, Hamburg
  A longitudinal broadband damper system to control coupled bunch instabilities has recently been constructed and installed in the 920~GeV proton accelereator HERA-p at the Deutsches Elektronen-Synchrotron DESY. This represents one of the attempts to increase the specific luminosity at HERA by reducing the bunch length. The final bunch length is defined by the initial emittance after injection and by the acceleration process where multiply occuring coupled bunch instabilities provoke bunch length blow up at discrete energies during the ramp. The actual feedback design consists of a fast, high precision bunch centroid phase detector, a 1~kW feedback cavity with 104~MHz centre frequency and 8~MHz bandwidth (FWHM), a I/Q-vector modulator, the low level digital FPGA-board with 14 Bit ADCs and DACs and a cavity transient diagnostics. The system measures the phases of all bunches and calculates corrections in real time (bunch spacing: 96~ns) which are then applied to the beam via a longitudinal kicker. The filter deals with a slowly changing synchrotron frequency (20-80 Hz).  
 
THPCH087 Design and Operation of a Ferrite Loaded Kicker Cavity for the Longitudinal Coupled Bunch Feedback for HERA-p resonance, damping, impedance, feedback 2991
 
  • J. Randhahn, S. Choroba, M. Dohlus, M. Ebert, F.E. Eints, M.G. Hoffmann, R. Wagner
    DESY, Hamburg
  A longitudinal broadband damper system to control coupled bunch instabilities has recently been constructed and installed in the 920 GeV proton accelereator HERA-p at the Deutsches Elektronen-Synchrotron DESY. The goal of this system is to reduce the bunch length and thus increase specific luminosity at HERA-p. Within the control system a kicker cavity is used as an actuator. The original aspect of this cavity lies in the simple geometry with no need for vacuum inside the cavity and high shunt impedance despite an internal ferrite load. The ferrite load is succesfully used to dampen higher order modes down to Q < 50 while the fundamental mode is damped by less than 2 dB. While nominal input power is rated at 60 dBm the cavity is prepared to handle beam loading. In spite of power requirements and ferrite load the cavity needs no active cooling. It can be tuned in center frequency and bandwidth over a range of 96..105 MHz and 4..7 MHz respectively and in consequence provides an optimal actuator for the particle beam control system. Presented will be the design details, all relevant parameters, the design of the internal ferrite load and operational experience.  
 
THPCH088 A Possibility of Constant Energy Extraction at the KEK ATF2 extraction, KEK, synchrotron, feedback 2994
 
  • A. Kalinin
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Beam energy oscillations of the order of 0.02% take place at the KEK ATF. With extractions, the synchrotron oscillation amplitude and phase at the extraction turn randomly fluctuates. The energy jitter causes a position/angle jitter in the Diagnostic section of the Extraction Line. To reduce it, a feed forward energy stabilisation can be used done by extraction of the beam at the turn next to that turn at which the energy passes the equilibrium value. For this, the synchrotron oscillation is measured by a turn-by-turn BPM as a horizontal position oscillation. A fast turn-by-turn processor detects the turn where the oscillation passes zero, and generates an extraction permission signal that triggers the existing ATF Extraction system. Stability improvement by factor of 10 can be obtained even when the extraction is done with uncertainty up to three turns after the trigger.  
 
THPCH092 Single-loop Two-dimensional Transverse Feedback for Photon Factory FIR, feedback, damping, factory 3006
 
  • T. Nakamura, K. Kobayashi
    JASRI/SPring-8, Hyogo-ken
  • W.X. Cheng, T. Honda, M. Izawa, T. Obina, M. Tadano
    KEK, Ibaraki
  We installed a 500MS/s single-loop two-dimensional transverse bunch-by-bunch feedback system in the Photon Factory ring at KEK and the system is in operation at its user mode. The system composed of a single feedback loop; one skewed pair of BPM electrodes and one kicker stripline at skewed position to detect position and kick horizontally and vertically with a single signal line, and a SPring-8 feedback processor. Consequently, this system is easy to tune and cost effective. SPring-8 feedback processor employs FPGA that has enough computing power for processing more than 20-tap FIR filter required for newly developed two-dimensional feedback signal processing. We report the principle of the system, the result of test and the experience.  
 
THPCH093 Bunch-by-bunch Feedback for the Photon Factory Storage Ring feedback, damping, impedance, controls 3009
 
  • W.X. Cheng, T. Honda, M. Izawa, T. Obina, M.T. Tadano, M. Tobiyama
    KEK, Ibaraki
  • K. Kobayashi, T. Nakamura
    JASRI/SPring-8, Hyogo-ken
  After the straight-section upgrade in 2005, the PF (Photon Factory) ring will start the top-up operation or the continuous mode in 2006. Previously the octupole magnets were used to suppress the transverse coupled bunch instability and RF modulation method to enhance the bunch length has been effectively used to suppress the longitudinal instabilities. However, such kind of methods are not suitable for the top-up operation, we are preparing active bunch-by-bunch feedback systems for both transverse and longitudinal plane. The transverse feedback system has been installed along with the straight-section upgrade, this system uses a FPGA based feedback processor board developed at the SPring-8, both horizontal and vertical signals are processed in a single control loop. For the longitudinal feedback, a two-port DAFNE type wide-band cavity has been designed and is now manufacturing, a digital signal processing part is under design, the whole system will start commissioning in autumn 2006.  
 
THPCH095 Transverse Damping System at SIS100 feedback, damping, injection, GSI 3014
 
  • V. Zhabitsky, E. Gorbachev, N.I. Lebedev
    JINR, Dubna, Moscow Region
  • U. Blell, P.J. Spiller
    GSI, Darmstadt
  The basic concept and main design features of the transverse damping system at the SIS100 synchrotron are presented. SIS100 with five times the circumference of the current SIS18 accelerator is a part of the Facility for Antiproton and Ion Research (FAIR) which is the next accelerator complex being constructed on the GSI site. The existing GSI accelerators serve as injector for SIS100. The SIS100 synchrotron will provide ion beams of high intensities which can lead to transversal and longitudinal beam instabilities. In order to damp the coherent transverse beam oscillations, a transverse feedback system (TFS) is going to be implemented in SIS100. The TFS presented is a feedback with a real-time digital signal processing for damping of transverse injection oscillations, feedback curing transverse coupled bunch instabilities, and excitation of transverse oscillations for beam measurements and other applications. The data on the bandwidth and gain of the TFS as well as the general description of the central processing unit are presented.  
 
THPCH097 Commissioning of the Digital Transverse Bunch-by-bunch Feedback System for the TLS feedback, FIR, damping, controls 3020
 
  • K.H. Hu, J. Chen, P.J. Chou, K.-T. Hsu, S.Y. Hsu, C.H. Kuo, D. Lee, C.-J. Wang
    NSRRC, Hsinchu
  • A. Chao
    SLAC, Menlo Park, California
  • K. Kobayashi, T. Nakamura
    JASRI/SPring-8, Hyogo-ken
  • W.-T. Weng
    BNL, Upton, Long Island, New York
  Multi-bunch instabilities degrade the beam quality leading to increased beam emittance, energy spread or even to beam loss. The feedback system is used to suppress multi-bunch instabilities due to resistive wall of the beam ducts, cavity-like structures and trapped ions. A new digital transverse bunch-by-bunch feedback system was commissioned at the Taiwan Light Source recently, and has replaced the previous analog system. The new system has the advantages that it enlarges the tune acceptance compared with the old system, enhances damping for transverse instability at high current, and as a result, top-up operation was achieved. In this new system, a single feedback loop simultaneously suppresses both the horizontal and vertical multi-bunch instabilities. The feedback system employs the latest generation FPGA feedback processor to process bunch signals. Memory installed to capture up to 250 msec bunch oscillation signal has included the considerations for system diagnostic and should be able to support various beam physics study.  
 
THPCH098 FPGA-based Longitudinal Bunch-by-bunch Feedback System for TLS feedback, FIR, impedance, synchrotron 3023
 
  • C.H. Kuo, J. Chen, P.J. Chou, K.-T. Hsu, S.Y. Hsu, K.H. Hu, W.K. Lau, D. Lee, C.-J. Wang, M.-H. Wang, M.-S. Yeh
    NSRRC, Hsinchu
  • M. Dehler
    PSI, Villigen
  • K. Kobayashi, T. Nakamura
    JASRI/SPring-8, Hyogo-ken
  A FPGA Based Longitudinal Bunch-by-Bunch Feedback System for TLS is commissioning recently to suppress strong longitudinal oscillation. The system consists of pickup, Bunch oscillation detector, FPGA based feedback processor borrow form the design of Spring8. Modulator converts the correction signal to the carrier frequency and longitudinal kicker which was re-designed form SLS' and working at 1374 MHz. The feedback processor is based upon latest generation FPGA feedback processor to process bunch signals. The memory capture is up to 250 msec bunch oscillation signal. The software and hardware design are also included for system diagnostic and support various beam physics study. Preliminary commission result will be summaried in this report.  
 
THPCH104 Design and Simulation of the ILC Intra-train Orbit and Luminosity Feedback Systems feedback, luminosity, simulation, linac 3041
 
  • G.R. White, G.R. White
    JAI, Oxford
  • D. Schulte
    CERN, Geneva
  • N.J. Walker
    DESY, Hamburg
  To maintain luminosity to within a few percent of the design at the International Linear Collider (ILC), beam stability at the IP needs to be maintained at the sub-nanometre level. To achieve the beam stability required in the presence of ground motion, multiple feedback systems are required. The baseline design calls for a 5-Hz system to control the orbit in the Linac and Beam Delivery System (BDS) and an intra-train system to address high-frequency ground motion and mechanical disturbances which cause orbit distortions at the IP between pulses enough to completely destroy the luminosity. Details of the slower feedback systems have been addressed elsewhere*. The detailed design and simulation of the intra-train feedback systems are described here. This system controls the vertical position and angle at the IP such that luminosity is maximised. The system brings the beams into collision based on BPM-derived information from the initial bunches of the train. It then tunes the IP collision parameters (both position and angle) based on a fast (bunch-by-bunch) luminosity signal from the BeamCal. The system is implemented in fast digital FPGA logic, designed using Matlab's Simulink.

*A. Seryi et al. "Issues of Stability and Ground Motion in ILC", Nanobeam 2005.**G. White et al. "Multi-Bunch Simulations of the ILC for Luminosity Performance Studies", PAC2005.

 
 
THPCH130 Design and Implementation of Analog Feedback Damper System for an Electron-proton Instability at the Los Alamos Proton Storage Ring feedback, storage-ring, LEFT, impedance 3104
 
  • C. Deibele, S. Assadi, V.V. Danilov, S. Henderson, M.A. Plum, C. Sibley III
    ORNL, Oak Ridge, Tennessee
  • S. Breitzmann, S.-Y. Lee
    IUCF, Bloomington, Indiana
  • J.M. Byrd
    LBNL, Berkeley, California
  • J.D. Gilpatrick, R.J. Macek, R.C. McCrady, J.F. Power, J. Zaugg
    LANL, Los Alamos, New Mexico
  The PSR (Proton Storage Ring) at LANSCE has observed an E-P (electron-proton) instability. A wideband analog feedback damper system was designed and implemented that has shown it is possible to correct this instability. The damper system consists of two 180 degree hybrids, low level amplifiers, a delay line, comb filter, power amplifiers, and adjustable delay lines. The system bandwidth is about between 10-300 MHz, and was developed and implemented in stages showing improvement in the e-p threshold of the buncher voltage. The system takes advantage of fiber optic technology for delays as well as for the comb filter. A system description and some measurement results are presented.  
 
THPCH143 The Fast Extraction Kicker System in SPS LSS6 SPS, extraction, impedance, LHC 3125
 
  • E.H.R. Gaxiola, F. Caspers, L. Ducimetière, P. Faure, T. Kroyer, B. Versolatto, E. Vossenberg
    CERN, Geneva
  A new fast extraction has been set up in SPS LSS6 to transfer 450 GeV/c protons as well as ions to Ring 1 of the LHC, via the transfer line TI 2. The system includes four travelling wave kicker magnets, recuperated from earlier installations and upgraded to fit the new application. All four magnets are powered in series, energised by a single PFN generator and terminated by a short circuit. The layout and the modifications to the magnets and the high voltage circuit are described along with the impact of design choices on the performance of the system. Results from laboratory tests and first machine experience are reported on approaches to overcome the effects of the beam induced kicker heating observed earlier, including a beam screen in form of metallic stripes printed directly onto the ferrites and the use of ferrite blocks with high Curie temperature. Prospects for further improvements are briefly discussed.  
 
THPCH147 Solid-state High Voltage Pulse Power in the 10-100 Nanosecond Regime damping, collider, insertion, linear-collider 3134
 
  • M.A. Kempkes, F.O. Arntz, N. Butler, J.A. Casey, M.P.J. Gaudreau
    Diversified Technologies, Inc., Bedford
  New particle accelerators, with voltages exceeding 50 kV and currents exceeding 1,000 A, require kicker magnet drivers to deliver pulsed power with durations in the 10-100 ns range. Similar levels of pulse performance are needed for state-of-the-art eximer laser systems, impulse radar transmitters, and particle accelerators for medical therapy. In addition, the processing of food using pulsed electric fields (PEF processing) has similar requirements. In this paper, DTI will review solid-state pulse power technologies capable of delivering high-voltage, high-current pulses with 10-to-100 nanosecond pulse duration. IGBTs, MOSFETs, snap-off diodes, and magnetic pulse compression will be discussed. Current research at Diversified Technologies, Inc. is exploring the impact of these switching devices and circuits on pulse wave shape, pulse repeatability, adjustability of pulse voltage, current and timing, maximum pulse rate (PRF), jitter, and robustness.  
 
THPCH148 Tests of a High Voltage Pulser for ILC Damping Ring Kickers damping, extraction, linac, injection 3137
 
  • M.A. Palmer, G. Dugan, D. L. Rubin
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • R. Meller
    Cornell University, Department of Physics, Ithaca, New York
  The baseline configuration for the International Linear Collider (ILC) damping rings specifies a single 6 km damping ring for electrons and two 6 km rings for positrons. Kicker requirements are determined by the damping ring circumference and the train structure in the main linac. The nominal bunch train parameters in the ILC main linac are trains of 2820 bunches with 308 ns spacing and a train repetition rate of 5 Hz. This means that the pulsers for the damping ring kickers must have rise and fall times suitable for bunch spacings of ~6 ns, must be able to operate with 3.25 Mhz bursts, and must support an average pulse rate of 14.1 kHz. We describe bench and beam tests of a pulser based on fast ionization dynistor technology whose specifications roughly meet these requirements. We then discuss the implications of our results for the ILC damping ring kickers.  
 
THPCH186 Magnetic Field Measurement and Fine-tuning of Kickers injection, storage-ring, synchrotron, synchrotron-radiation 3236
 
  • T.-C. Fan, C.-H. Chang, C.-S. Fann, C.-S. Hwang, F.-Y. Lin
    NSRRC, Hsinchu
  We have demonstrated an algorithm which promisingly can tune the pulse shape of current and magnetic field of kicker systems in-situ. This algorithm includes gap shimming of the ferrite magnets to adjust the pulse width of the excitation current and changing the resistance of the secondary coils to modify the pulse curvatures of each kicker. With the empirical formula derived from the systematic measurement on the magnetic field and the pulse current in laboratory, we can reduce the pulse-shape difference among the kicker magnets in the injection section of the storage ring, with no need to do anything on the pulsers and high voltage power suppliers. This approach can efficiently increase the injection efficiency which is demanding in the top-up injection mode adopted by many new facilities of synchrotron radiation.  
 
THPCH187 Analysis and Reduction Electromagnetic Interference to ICTs Caused by Pulsed Power Supply Excitation in NSRRC injection, electron, power-supply, storage-ring 3239
 
  • Y.-H. Liu, J.-C. Chang, J.-R. Chen, Y.-C. Lin
    NSRRC, Hsinchu
  The purpose of this paper is to eliminate the Electromagnetic Interference (EMI) from kicker power supply. Analyses of the EMI source and the propagation path are the beginning missions. The radiated and conducted EMI both affected the Integral Current Transformer (ICT) normal operation because of the space limitation for TLS in NSRRC. The ICT is to measure injection efficiency, thus, ICT located just behind the kickers and using the common girder. The EMI signals therefore are much higher than the electron beam currents, and the integral values of the sensor are not correct. For reducing and eliminating the interference of electromagnetic waves, a hybrid segregation and grounding method was used. The EMI wrapper was enclosed the ICT and its high frequency amplifier separately to prevent the radiated EMI from the space. The grounding paths provided the possible stray current dredge to the ground loop. It reduced the stray current spread to the subsystems next to the kickers. The EMI therefore reduced 99%, and the injection efficiency could be calculated successfully. The elimination of the EMI from kicker itself will be the next step in the future.  
 
THPLS028 Pulsed Magnets and Pulser Units for the Booster and Storage Ring of the Diamond Light Source booster, septum, storage-ring, injection 3341
 
  • V.C. Kempson, J.A. Dobbing
    Diamond, Oxfordshire
  • C.E. Hansen, N. Hauge, G. Hilleke
    Danfysik A/S, Jyllinge
  The Diamond booster and storage ring complex require ten pulsed magnet systems, five for the booster (injection and extraction) and five for the storage ring injection. Each has its own specific design criteria, although commonality of approach has been applied wherever possible. This paper describes the design principles and construction method for the various systems and presents the results of power supply tests and magnetic measurements. Finally, initial experience during the Diamond beam commissioning is discussed.  
 
THPLS078 Tests of a New Bunch Cleaning Technique for the Advanced Light Source injection, storage-ring, betatron, controls 3463
 
  • F. Sannibale, W. Barry, M.J. Chin
    LBNL, Berkeley, California
  A new bunch cleaning technique is being tested at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory. The new procedure allows for high purity, arbitrary filling patterns and is potentially compatible with standard user operation and with the incoming top-off injection mode. The description of the new system and the results of the first tests at the ALS are presented.  
 
THPLS099 Fast Kicker Systems for the SOLEIL Booster Injection and Extraction, with Full Solid-state Pulsed Power Supplies extraction, injection, power-supply, vacuum 3505
 
  • P. Lebasque, M. Bol, C. Herbeaux, J.-P. Lavieville, J.L. Marlats
    SOLEIL, Gif-sur-Yvette
  The Booster of SOLEIL needs injection and extraction kicker systems with fast transition times, good flat top and low jitter, to allow a satisfactory injection efficiency of the Storage Ring injection. So all the kicker systems have been optimised, to fulfil specifications and to permit the use of solid state switching electronics. This contribution presents the ceramic vacuum chambers and magnets design, the specific pulse forming scheme and the realisation of the pulsed power supplies working up to 20 kV. Electrical and magnetic measurements results of kickers systems are given, and also its operation status from the first SOLEIL Booster injection in July 2005.  
 
THPLS100 Four Matched Kicker Systems for the SOLEIL Storage Ring Injection, a Full Solid State Solution of Pulsed Power Supplies Working at High Current storage-ring, SOLEIL, vacuum, injection 3508
 
  • P. Lebasque, R. Ben El Fekih, C. Herbeaux, J.-P. Lavieville, J.L. Marlats
    SOLEIL, Gif-sur-Yvette
  The Top Up injection mode of the SOLEIL Storage Ring needs a very good matching of the four kicker magnet fields. But their implantation inside the straight section dedicated to SR injection imposed high level forces on each of the four kickers. This contribution describes the ceramic vacuum chambers and magnets design optimised to provide a very good identity of the four magnets. The pulsed power supplies, based on IGBT high voltage modules, designed to work at high current (5250 A-9000 V) could be located outside the SR tunnel. We highlight the specific development on all components specification and electrical scheme that permits to reach such a challenge. The electrical and magnetic measurement results are reported.  
 
THPLS102 Optimisation of the Coating Thickness on the Ceramic Chambers of the SOLEIL Storage Ring injection, SOLEIL, vacuum, storage-ring 3514
 
  • P. Lebasque, L. Cassinari, J.P. Daguerre, C. Herbeaux, M.-P. Level, C. Mariette, R. Nagaoka
    SOLEIL, Gif-sur-Yvette
  The SOLEIL storage ring injection section integrates four matched injection kicker magnets, two diagnostics kicker magnets and a beam shaker, which need ceramic vacuum chambers with an inner titanium coating. For each utilisation (according with its field amplitude and its time or frequency domain), the coating thickness has been evaluated from the different points of view: field attenuation, beam deposited power, magnet excitation deposited power, and cooling efficiency. So we could determine the different coating thicknesses and tolerances needed according to the different magnetic field shapes. The realised ceramic chambers have adequate coating resistances, with in particular a low non-uniformity among the matched injection kicker magnets chambers.  
 
THPLS110 Injection Scheme for TPS Storage Ring injection, storage-ring, septum, lattice 3535
 
  • M.-H. Wang, H.-P. Chang, C.-C. Kuo, G.-H. Luo
    NSRRC, Hsinchu
  Taiwan Photon Source(TPS), a 3~3.3 GeV synchrotron light source with full energy injection is proposed to be built at NSRRC in Taiwan. In this paper we report the design of injection scheme for TPS. The space allocation of the injection components, the bumper design, the aperture consideration and the injection dynamics of injected and stored beam will all be discussed. The particle tracking of first few turns of injection is performed to evaluate the injection efficiency with the errors caused by the time jitter and amplitude stability of injection kickers. The issue of constant current operation will be also addressed.  
 
THPLS113 Design of a Fast Extraction Kicker for the Accelerator Test Facility impedance, extraction, damping, SLAC 3544
 
  • S. De Santis, A. Wolski
    LBNL, Berkeley, California
  • M.C. Ross
    SLAC, Menlo Park, California
  We present a study for the design of a fast extraction kicker to be installed in the Advanced Test Facility ring. The purpose of the project is to test the technologies to be used in the design of the extraction kickers for the ILC damping rings. The kicker's rise and fall times are important parameters in the design of the damping rings, as they limit the minimum distance between bunches and ultimately define a lower boundary for the ring length. We propose a stripline kicker composed of several 20-cm long sections, grouped in two locations in the ATF damping ring. An analytical study of the kicker's parameters and computer simulations using Microwave Studio* point out the strict requirements on the pulsers, in order to be able to satisfy the design parameters.

*http://www.cst.com

 
 
THPLS114 "CAMSHAFT" Bunch Kicker Design for the ALS Storage Ring storage-ring, vacuum, pick-up, feedback 3547
 
  • S. Kwiatkowski, K.M. Baptiste, W. Barry, J. Julian, L. Low, D.W. Plate, G.J. Portmann, D. Robin
    LBNL, Berkeley, California
  ALS is a 1.9 GeV third generation synchrotron light source that has been operating since 1992 at Lawrence Berkeley National Laboratory. There are two typical modes of operation of the ALS storage ring. In multibunch mode, the ring is filled to a current of 400 mA in 276 consecutive bunches with a single "camshaft" bunch located in the middle of the 52 bucket gap (h=328). Twice each year, ALS operates in "two-bunch" mode for periods of two weeks delivering 20 mA of average beam current in two diametrically opposite bunches to a small group of users requiring light pulses at lower rates. We plan to build a fast kicker system that will supply single bunch light to users during multibunch operation by displacing the orbit of the camshaft bunch at a prescribed frequency (every N turns). Realization of this project will increase ALS beam availability to multibunch users by at least 10%. This paper will describe the hardware design (pulse generator and beam deflection device) and the test results of the prototype kicker unit.