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kicker

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MOPC062 Results from ALICE (ERLP) DC Photoinjector Gun Commissioning emittance, laser, gun, electron 208
 
  • Y. M. Saveliev, D. J. Holder, B. D. Muratori, S. L. Smith
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  The Energy Recovery Linac Prototype (ERLP) DC photoinjector gun has been commissioned and the beam characteristics measured. The gun has demonstrated the nominal ERLP parameters of 350 keV electron energy, 80pC bunch charge and ~140 ps bunch length (at 10% level). The bunch parameters were measured at different bunch charges from 1 pC up to 80 pC. Special attention was given to measurements of the beam transverse emittance (using a movable slit), correlated and uncorrelated energy spread (using an energy spectrometer) and bunch length (using a transverse RF kicker) at each bunch charge. The effect of the 1.3 GHz RF buncher on the bunch length was also investigated. The experimental results are then compared with ASTRA simulations. Experimental results obtained from the investigation of several other issues including the beam characteristics in the presence of field emission from the cathode and in the presence of strong beam halo are also presented and discussed.  
 
MOPC128 J-PARC Accelerator Scheme for Muon to Electron Conversion Search extraction, proton, emittance, background 367
 
  • M. Tomizawa
    KEK, Ibaraki
  • M. Aoki, I. Itahashi
    Osaka University, Osaka
  The searching for coherent neutrino-less conversion of a muon to an electron (COMET) at sensitivity of 10?16 has been proposed as an experiment using the J-PARC Nuclear and Particle Experimental (NP) Hall. The experiment is planned to utilize a 56 kW, 8 GeV-bunched proton beam slowly extracted from the J-PARC main ring. The 1 MHz beam pulsing with an extremely low bunch to bunch gap background is needed to eliminate beam-related background events and keep an experimental sensitivity as high as possible. The 8 GeV extraction energy is rather lower than an ordinary energy. The beam size must be less than apertures of the extracted orbit in the ring and the transport line to the NP Hall. Accelerator scheme to satisfy above requirements will be reported in this paper.  
 
MOPP017 A Kicker Driver Exploiting Drift Step Recovery Diodes for the International Linear Collider damping, instrumentation, linear-collider, collider 589
 
  • F. O. Arntz, M. P.J. Gaudreau, A. Kardo-Sysoev, M. K. Kempkes, A. Krasnykh
    Diversified Technologies, Inc., Bedford, Massachusetts
  Diversified Technologies, Inc. (DTI) is developing a driver for a kicker strip-line deflector which inserts and extracts charge bunches to and from the electron and positron damping rings of the International Linear Collider. The kicker driver must drive a 50 Ω terminated TEM deflector blade at 10 kV with 2 ns flat-topped pulses, which according to the ILC pulsing protocol, bursts pulses at a 3 MHz rate within one-millisecond bursts occurring at a 5 Hz rate. The driver must also effectively absorb high-order mode signals emerging from the deflector. In this paper, DTI will describe current progress utilizing a combination of high voltage DSRDs (Drift Step Recovery Diodes) and high voltage MOSFETs. The MOSFET array switch, without the DSRDs, is itself suitable for many accelerator systems with 10 – 100 ns kicker requirements. DTI has designed and demonstrated the key elements of a solid state kicker driver which both meets the ILC requirements, is suitable for a wide range of kicker driver applications. Full scale development and test are exptected to occur in Phase II of this DOE SBIR effort, with a full scale demonstration scheduled in 2009.  
 
MOPP025 Design of the Beam Extraction by Using Strip-line Kicker at KEK-ATF septum, extraction, injection, damping 601
 
  • T. Naito, H. Hayano, K. Kubo, S. Kuroda, T. Okugi, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  The developing work of the strip-line kicker system for International linear collider(ILC) is carrying out at KEK*. To confirm the performance of the kicker system, the beam extraction test by using strip-line kicker is in progress at KEK-ATF. The multi-bunch beam, which has 2.8ns bunch spacing in the damping ring, is extracted from the damping ring to the extraction line with 308ns duration. The scheme is the same as the kicker of the ILC. The bump orbit and the auxiliary septum magnet will be used with the kicker to clear the geometrical restriction. The detail of the hardware design and the basic performance of each component are presented in this paper.

*T. Naito et al. Development of the Strip-line Kicker System for ILC Damping Ring, Proceedings of PAC07, Albuquerque, New Mexico, USA, pp2772-2274.

 
 
TUPC084 Combating Multi-bunch Instabilities with the Libera Bunch-by-bunch Unit feedback, betatron, single-bunch, target 1251
 
  • V. Poucki, T. Karcnik, P. L. Lemut, M. O. Oblak
    Instrumentation Technologies, Solkan
  Libera Bunch by Bunch is the digital processing unit for a bunch by bunch feedback system. The upgraded unit has a DSP core application featuring a 16 tap filter for each bunch. DSP processing is organized in 4 chains, following the HW implementation of A/D conversion. Besides setting of FIR filter coefficients in each processing chain, one bunch per chain can have different FIR filter coefficients and provides an option for 4 single bunch processing. All FIR filter coefficients are double buffered. Delays maximally equal to a revolution period are implemented before and after the FIR block. As an additional feature, a phase shift block is introduced that precisely shifts the phase of the output signal in the vicinity of a determined frequency. The core application is accompanied with a Matlab GUI, with an additional window for data acquisition. This system accompanied by a Front End unit provides a complete solution for combating multi bunch beam instabilities. A detailed description and results are presented.  
 
TUPD003 Upgrading the Fast Extraction Kicker System in SPS LSS6 extraction, impedance, proton, pick-up 1437
 
  • M. J. Barnes, L. Ducimetière, B. Goddard, J. A. Uythoven
    CERN, Geneva
  A fast extraction system, located in the LSS6 region of the CERN SPS accelerator, transfers 450 GeV/c protons, as well as ions, via the transfer line TI 2 towards the LHC. The system includes three travelling wave kicker magnets, all powered in series, energised by a single Pulse Forming Network (PFN) and terminated by a short circuit. The specification for the system requires a kick flattop of 7800 ns duration with a ripple of not more than ±0.5%. Recent measurements with beam show that the ±0.5% kick specification is achieved over the initial 7100 ns of the kick flattop; however the ripple over 7800 ns is ±0.7%. Electrical measurements have been carried out on each of the three magnets: these have been compared with the beam measurements and the contribution of each magnet to the detailed shape of the flattop kick has been determined. This paper reports the results of measurements and describes the plans to upgrade the system to fully meet the kick specification.  
 
TUPD004 10Hz Pulsed Power Converters for the ISIS Second Target Station(TS-2) pulsed-power, controls, proton, power-supply 1440
 
  • S. L. Birch, S. P. Stoneham
    STFC/RAL/ISIS, Chilton, Didcot, Oxon
  The Extracted Proton Beamline to the ISIS second target station has two 10Hz pulsed magnet systems which extract the proton beam from the existing 50Hz beamline. Kicker 1 magnet system deflects the beam 12.1mrad and kicker 2 magnet system deflects the beam 95mrad. Both magnets are identical, however each pulsed power converter is considerably different. This paper describes the design requirements, topology, installation, testing and successful operation of both pulsed power converters.  
 
TUPD006 The Injection and Extraction Kicker Circuits for the Elettra Booster extraction, injection, booster, storage-ring 1443
 
  • R. Fabris, P. Tosolini
    ELETTRA, Basovizza, Trieste
  The design, realization and performance of the power circuits for the Booster injection and extraction Kicker magnets are presented. Both circuits have been designed and developed with the goal to achieve reliable working conditions, simple maintenance and fast recovery time in case of failures. The circuits are designed around the same switching unit already adopted in the Kicker system of the Storage Ring injection; this allows storing common spare parts for both circuits and for the Storage Ring Kicker system as well. Beside the analytical analysis, a parametric study of the circuit, with the Microsim PSPICE software package, allowed to optimize the performance of the circuit regarding the parameters which were considered critical for the Booster injection and extraction processes, i. e. the current pulse rise time and fall time.  
 
TUPD007 The Design and Fabrication of the Kicker Power Supply for TPS Project injection, storage-ring, power-supply, photon 1446
 
  • C.-S. Fann, K. T. Hsu, S. Y. Hsu, K.-K. Lin, K.-B. Liu, Y.-C. Liu, C. Y. Wu
    NSRRC, Hsinchu
  The preliminary test results of the kicker power supply for TPS (Taiwan Photon Source) project will be presented in this report. The achieved capability of this test unit demonstrates that it fulfills the design requirement of providing half-sine pulsed current of 2.5 kA (peak), 5.2 s (base-width), with jitter < 1 ns (peak-to-peak). Both units of using thyratron and IGBT switches are built with the same requirements. The technical considerations of both units for this particular application will be discussed.  
 
TUPD010 High-power Switch with SI-thyristor for the Power Supply of Very High Repletion Rate Pulsed Quadrupole Magnet quadrupole, power-supply, induction, positron 1452
 
  • T. Mimashi, M. Kikuchi
    KEK, Ibaraki
  • A. Tokuchi, K. Tsuchida
    Nichicon (Kusatsu) Corporation, Shiga
  A solid-state switch with SI-thyristors is implemented as the high power switch for the pulsed quadrupole magnet power supply. Its repletion rate is 100 kHz with the half sign 1 microsecond pulse. The switch has been successfully operated.  
 
TUPD014 Detailed Design, Manufacturing and Testing of a Strip-line Extraction Kicker for CTF3 Combiner Ring simulation, vacuum, impedance, extraction 1458
 
  • I. Rodriguez, L. García-Tabarés, E. Rodríguez García, F. Toral
    CIEMAT, Madrid
  • D. Alesini, A. Ghigo, F. Marcellini, M. Zobov
    INFN/LNF, Frascati (Roma)
  • T. Fowler, I. Syratchev
    CERN, Geneva
  The first calculations to design the CTF3 Combiner Ring extraction kicker are reported elsewhere. The last computing step before fabrication is the wakefield analysis, to determine if the bunch disturbance is acceptable. Two different codes have been used for cross-checking: CST Particle Studio and GDFidl. The computation is challenging because of the long structure (2.4 m) with a short bunch (3 mm). Besides, both transitions are not equal, because of different straight sections of the input and output beam pipe, and then the solution method is more complex. On the other hand, the main challenges for manufacturing are the long electrodes support via ceramic stand-offs and the flexible electrical connections to allow for electrodes thermal differential displacement. Special tooling has also been developed for assembly within the required tolerances. The device has been successfully leak tested. High frequency transmission coefficients and high voltage dielectric strength were also measured.  
 
TUPP043 Computational Beam Dynamics Studies of Collective Instabilities Observed in SNS proton, simulation, electron, impedance 1640
 
  • J. A. Holmes, S. M. Cousineau, V. V. Danilov, A. P. Shishlo
    ORNL, Oak Ridge, Tennessee
  • L. K. Jain
    UW/Physics, Waterloo, Ontario
  During the commissioning and early operation of the Spallation Neutron Source, some physcics shifts were set aside for high intensity stability studies. Under certain, especially contrived conditions, a number of beam instabilities were induced. These included both electron cloud and ring impedance driven phenomena. In this paper we apply both simple analytic models and the ORBIT Code to the description and simulation of these observed instabilities.  
 
TUPP066 CERN SPS Impedance in 2007 impedance, quadrupole, shielding, synchrotron 1691
 
  • E. Métral, G. Arduini, T. Bohl, H. Burkhardt, F. Caspers, H. Damerau, T. Kroyer, H. Medina, G. Rumolo, M. Schokker, E. N. Shaposhnikova, J. Tuckmantel
    CERN, Geneva
  • R. Calaga
    BNL, Upton, Long Island, New York
  • B. Salvant
    EPFL, Lausanne
  • B. Spataro
    INFN/LNF, Frascati (Roma)
  Each year several measurements of the beam coupling impedance are performed in both longitudinal and transverse planes of the CERN Super Proton Synchrotron to keep track of its evolution. In parallel, after the extensive and successful campaign of identification, classification and cure of the possible sources of (mainly longitudinal) impedance between 1998 and 2001, a new campaign (essentially for the transverse impedance this time) has started few years ago, in view of the operation of the SPS with higher intensity for the LHC luminosity upgrade. The present paper summarizes the results obtained from the measurements performed over the last few years and compares them to our predictions. In particular, it reveals that the longitudinal impedance is reasonably well understood and the main contributors have already been identified. However, the situation is quite different in the transverse plane: albeit the relative evolution of the transverse impedance over the last few years can be well explained by the introduction of the nine MKE kickers necessary for beam extraction towards the LHC, significant contributors to the SPS transverse impedance have not been identified yet.  
 
TUPP067 Transverse Mode-coupling Instability in the CERN SPS: Comparing MOSES Analytical Calculations and HEADTAIL Simulations with Experiments in the SPS simulation, impedance, injection, coupling 1694
 
  • B. Salvant
    EPFL, Lausanne
  • G. Arduini, E. Métral, G. Papotti, G. Rumolo, R. J. Steinhagen, R. Tomas
    CERN, Geneva
  • R. Calaga
    BNL, Upton, Long Island, New York
  Since 2003, single bunches of protons with high intensity (1.2·1011 protons) and low longitudinal emittance (0.2 eVs) have been observed to suffer from heavy losses in less than one synchrotron period after injection at 26 GeV/c in the CERN Super Proton Synchrotron (SPS) when the vertical chromaticity is corrected. Understanding the mechanisms underlying this instability is crucial to assess the feasibility of an anticipated upgrade of the SPS, which requires bunches of 4·1011 protons. Analytical calculations from MOSES and macroparticle tracking simulations using HEADTAIL with an SPS transverse impedance modelled as a broadband resonator had already qualitatively and quantitatively agreed in predicting the intensity threshold of a fast instability. A sensitive frequency analysis of the HEADTAIL simulations output was then done using SUSSIX, and brought to light the fine structure of the mode spectrum of the bunch coherent motion. A coupling between the azimuthal modes -2 and -3 was clearly observed to be the reason for this fast instability. The aim of the present paper is to compare the HEADTAIL simulations with dedicated measurements performed in the SPS in 2007.  
 
TUPP076 Longitudinal and Transverse Impedances of XFEL Kicker Vacuum Chamber impedance, vacuum, dipole, resonance 1712
 
  • A. V. Tsakanian, J. Rossbach
    Uni HH, Hamburg
  • M. Ivanyan
    CANDLE, Yerevan
  In European XFEL project beam delivery system the kicker magnet vacuum chamber design is composed of the ceramic pipe coated with Titanium Stabilized High Gradient Steel. In this paper the results of the study for the longitudinal and transverse impedances for such a laminated vacuum chamber are presented. The field matching technique is used to calculate the vacuum chamber impedances. The loss and kick factors are given.  
 
TUPP081 Longitudinal Wakefields and Impedance in the CSNS/RCS impedance, extraction, injection, vacuum 1718
 
  • N. Wang, Q. Qin
    IHEP Beijing, Beijing
  With the more general expressions developed for the wakefield generated by nonrelativistic beam*, the impedances of some main vacuum parts of the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) are calculated and compared with the relativistic case. An impedance model is then proposed for the ring. With this impedance model, beam instabilities in the CSNS/RCS are investigated.

*N. Wang and Q. Qin, Phys. Rev. ST Accel. Beams 10, 111003 (2007)

 
 
TUPP115 Variable Energy Protontherapy FFAG Accelerator extraction, injection, septum, proton 1791
 
  • J. Fourrier, J. Pasternak
    LPSC, Grenoble
  • M. Conjat, J. Mandrillon, P. Mandrillon
    AIMA, Nice
  • F. Meot
    CEA, Gif-sur-Yvette
  A hadrontherapy accelerator assembly based on an FFAG ring and a variable energy H- cyclotron injector has been designed in the frame of the RACCAM project. The FFAG ring allows 2.1 Tm top rigidity, corresponding to 180 MeV proton top energy and 21.6 cm penetration depth and to 50 MeV per nucleon for carbon ions suitable for biological R&D). Variable energy extraction, bunch to pixel 3D scanning and multiport beam delivery are proposed in this installation. A prototype of a spiral sector scaling type of FFAG dipole is being built for proving the feasibility of the FFAG ring, subject to a second contribution in the conference. This paper will describe the accelerator assembly parameters and the beam properties.  
 
WEZG01 Protection Controls for High Power Accelerators controls, diagnostics, target, injection 1921
 
  • J. Wenninger
    CERN, Geneva
  The next generation hadron accelerators will operate with MW beams or store beams with an energy of many 100 MJ. Machine protection will constrain operation, but some operational flexibility is still required for commissioning and performance optimization. This is a substantial challenge for control systems and application programs. New tools are developed to face those challenges: critical settings management, software interlocks, role based access to equipment, automatic accelerator mode recognition etc. This talk presents some of the challenges and tools. Experience with novel approaches are discussed.  
slides icon Slides  
 
WEOCG02 Post-mortem Diagnostic for the Taiwan Light Source diagnostics, insertion, controls, beam-losses 1932
 
  • K. H. Hu, J. Chen, P. C. Chiu, K. T. Hsu, S. Y. Hsu, C. H. Kuo, D. Lee, C.-J. Wang, C. Y. Wu
    NSRRC, Hsinchu
  Analyzing the reasons of various trip events is essential to improve reliability of a synchrotron light source. To identify the causes of trip at Taiwan Light Source (TLS), various diagnostics tool were employed. These diagnostic tools can capture beam trip, interlock signals of superconducting RF system, waveform of the injection kickers, quench and interlock signals of the superconducting insertion device, and instability signals of the stored beam for post-mortem analysis. These diagnostics can be routine monitor signal and record beam trip event. Features of trip diagnostic tools are available now. System configuration experiences will be summarized in this report.  
slides icon Slides  
 
WEOBM02 Lessons Learned from PEP-II LLRF and Longitudinal Feedback controls, feedback, klystron, simulation 1953
 
  • J. D. Fox, T. Mastorides, C. H. Rivetta, D. Van Winkle
    SLAC, Menlo Park, California
  • D. Teytelman
    Dimtel, San Jose
  The PEP-II B Factory is in the final phase of operation at 2X the design current and 4X the design luminosity. Since the original design the machine has added 8 1.2 MW Klystrons and 12 RF cavities, and the machine is operating with longitudinal instability growth rates roughly 5X in excess of the original estimates. Since commissioning there has been continual adaptation of the LLRF control strategies, configuration tools and new hardware in response to unanticipated technical challenges. This paper presents the LLRF and feedback system evolution from the original design estimates through to the 1.2·1034 final machine. We highlight issues of RF station stability, the interplay of LLRF configuration and low-mode (cavity fundamental driven) longitudinal instabilities, impacts of non-linearities and imperfections in the LLRF electronics, control of HOM driven beam instabilities and the development of configuration tools and measurement techniques to optimally configure the LLRF over the wide range of operating currents. We present valuable "lessons learned" which are of interest to designers of next generation impedance controlled LLRF systems.  
slides icon Slides  
 
WEPC005 Design Considerations of the TPS Linac-to-booster Transfer Line booster, linac, injection, septum 1989
 
  • H.-P. Chang, H. C. Chao, K. T. Hsu, S. Y. Hsu, D.-G. Huang, C.-C. Kuo, K.-K. Lin, W. T. Liu, Y.-C. Liu
    NSRRC, Hsinchu
  Design considerations of the linac to booster (LTB) transfer line for Taiwan Photon Source (TPS) project is described in this report. Electron beam from the linac with 150 MeV, 50 π-mm-mrad normalized emittance and 0.5% energy spread will be transferred to a booster synchrotron of 489.6 m. This LTB transfer line is designed with the flexible tuning capability and the diagnostics are included. Matching of transverse beam parameters from linac to booster is deliberated. The on-axis injection scheme with repetition rate around 2 or 3 Hz and efficiency with beta-mismatch for top-up operation is also studied.  
 
WEPC037 Preparations of BESSY for Top Up Operation injection, synchrotron, storage-ring, septum 2067
 
  • P. Kuske, M. Abo-Bakr, W. Anders, T. Birke, K. B. Buerkmann-Gehrlein, M. Dirsat, O. Dressler, V. Duerr, F. Falkenstern, W. Gericke, R. Goergen, F. Hoffmann, T. Kamps, J. Kuszynski, I. Mueller, R. Mueller, K. Ott, J. Rahn, T. Schneegans, D. Schueler, T. Westphal, G. Wuestefeld
    BESSY GmbH, Berlin
  • D. Lipka
    DESY, Hamburg
  The synchrotron light source BESSY went into operation for users in 1998. BESSY was not designed initially to allow for Top Up operation, a mode where lost electrons are replaced after minutes while the beam shutters are open and users take data. Since 3 years the facility is improved in order to guarantee safe operation in this risky mode. The work culminated in a one week long Top Up test run at the beginning of this year. The efforts and achievements are described in detail: Improvements of the injector, the pulsed injection elements, the timing system, insertion devices, the additional safety interlocks, and the shielding of the ring.  
 
WEPC041 The Injection System of the SSRF Storage Ring injection, storage-ring, septum, multipole 2076
 
  • H. H. Li, B. C. Jiang, L. G. Liu, X. Y. Sun, Y. Xu, W. Zhang, X. M. Zhou
    SINAP, Shanghai
  A multi-turn injection scheme with four kickers and two septa is used for injection into SSRF storage ring. The 3.5GeV electron beam from the SSRF booster is injected with 6.3 degrees horizontally. All injection elements are set in one 12m long straight section for the requirement of the top-up operation. Simulation and commissioning results will be presented in this paper, such as the injection efficiency and the disturbance on stored beam.  
 
WEPC049 Novel Schemes for Simultaneously Satisfying High Flux and TOF Experiments in a Synchrotron Light Source synchrotron, storage-ring, radiation, single-bunch 2100
 
  • D. Robin, G. J. Portmann, F. Sannibale, W. Wan
    LBNL, Berkeley, California
  Storage Ring Light Sources have proven to be extremeley succesful tools for probing matter. One of their most desirable features is that they are able to supply synchrotron radiation to multiple experiments simultaneously. However two classes of applications are difficult to satisfy simultaneously - high flux applications and time of flight applications. High flux experiments require filling as many buckets as possible while time of flight experiments require long gaps between bunches. In this paper we examine schemes for operating the synchrotron light source for for both communities simultaneously.  
 
WEPC068 Injection into the ALBA Storage Ring injection, septum, storage-ring, booster 2151
 
  • G. Benedetti, D. Einfeld, M. Munoz, M. Pont
    ALBA, Bellaterra
  • E. Huttel
    FZK, Karlsruhe
  Injection into the ALBA Storage Ring is performed at an energy of 3 GeV in a 7 m long straight section. The injection bump is performed with four kickers. Pulsed magnets are described, in particular the active septum magnet. Tracking of particles has been simulated over a large number of turns, taking into account the magnet errors, the sextupole fields and the physical apertures all along the machine. Specific requirements for top-up injection have been examined, such as a perfect closure of the injection bump, the residual vertical field and the leakage fields from the septum.  
 
WEPC073 Layout of the Beam Switchyard at the European XFEL septum, undulator, linac, collimation 2163
 
  • W. Decking, F. Obier
    DESY, Hamburg
  A unique feature of the European XFEL will be the possibility to distribute electron bunches of one beam pulse to different FEL beam lines. This is achieved by using a combination of fast kickers and a DC septum. Integration of a beam abortion dump allows a flexible selection of the bunch pattern at the FEL experiment, while the superconducting linear accelerator operates with constant beam-loading. We describe the principal scheme, the geometrical and optical layout and deal with stability and technical issues like the fast kicker development.  
 
WEPC074 The Injection and Extraction Kicker Magnets of the Elettra Booster extraction, vacuum, injection, booster 2166
 
  • R. Fabris, G. Pangon
    ELETTRA, Basovizza, Trieste
  The design, realization and performance of the injection and extraction Kicker magnets of the Booster of Elettra are presented. A window-frame geometry has been chosen due to its transverse symmetry in order to obtain a good field symmetry. A suitable layout for in vacuum operation has been developed. The magnetic core is made by CMD 5005 ferrite blocks, assembled in a stainless steel case, obtaining a single module; one module has been used for the injection Kicker and two such modules, connected in parallel, have been used for the extraction Kicker. In both cases the magnet modules have been installed in stainless steel vacuum chambers. The design of the magnetic core has been checked using the well known 2D POISSON code, thanks to the fact that the magnet’s gap is narrow compared to its length.  
 
WEPC077 Pulsed Magnet Systems for the SSRF Injection and Extraction injection, extraction, septum, storage-ring 2175
 
  • M. G. Gu, Z. H. Chen, B. Liu, L. Ouyang, R. Wang, Y. Wu, Q. Yuan
    SINAP, Shanghai
  The injector and the storage ring of the Shanghai Synchrotron Radiation Facility (SSRF) have been built and the commissioning procedure and results are satisfactory. Total of fourteen pulsed magnets are used for the SSRF injection and extraction. In-vacuum ferrite kicker magnets, eddy current septa and 200ms bump magnets are offered for booster injection and extraction. A symmetric bump of stored beam is performed in one of the long straight section of the SSRF storage ring. Four identical kickers with ceramic vacuum chamber and two septa with a sheet of magnetic screening material around the stored beam are equipped for the storage ring injection. The septa can reach maximum 900 Tm field at 8600A with less than 0.01% leakage field for stored beam. And the identical 3.8 us half-sine pulse waveform is excited on the kicker magnets with 3.6kA current and exacted timing. The stability of ±0.05% (rms), low leakage field and identical bump are emphasized so that the residual closed orbit disturbance can be minimized for top-up injection.  
 
WEPC081 Improvement on Pulsed Magnetic Systems at SOLEIL injection, vacuum, storage-ring, pulsed-power 2183
 
  • P. Lebasque, R. Ben El Fekih, M. Bol, J.-P. Lavieville, A. Loulergue, D. Muller
    SOLEIL, Gif-sur-Yvette
  Two "machine study" kicker systems have been designed, built and installed on the storage ring of SOLEIL to kick the stored beam in the horizontal and the vertical planes, in order to investigate the non-linear dynamic of the ring with different insertion devices configurations. This article will describe the different aspects of the design of the two magnets and vacuum chambers, and of their fast high current pulsed power supplies, working with high voltage switches based on MOS transistors. The electrical and magnetic measurements will be presented. The second part of the paper will describe the modifications brought to the thick septum magnet system of the ring injection, in view to reduce the stray field seen by the stored beam. It also presents the different tunings performed on the four injection kickers, in order to reduce the amplitude of the residual bump along the ring down to a very low level. Theses adjustements are aimed to minimize the disturbances on the stored beam when operating the Synchrotron in "Top Up" injection mode.  
 
WEPC093 Finalized Design of the Pulsed Magnets and their PS for SESAME Ring Injection septum, injection, vacuum, power-supply 2210
 
  • S. Varnasseri, A. Nadji
    SESAME, Amman
  • J.-P. Lavieville, P. Lebasque
    SOLEIL, Gif-sur-Yvette
  The design of the SESAME storage ring injection pulsed magnet systems have been improved in order to take benefit of the most recent realizations in Synchrotrons. These pulsed systems are optimised for the injection into the 2.5GeV storage ring of the 800 MeV electrons beam prepared by the Booster. The septum magnet is based on a direct driven septum technology, out of vacuum, with a thin vacuum chamber of rectangular cross section permitting to get a good field transverse homogeneity. The four kicker magnets will be of the window frame geometry, around a racetrack alumina vacuum chamber, integrating a forced air cooling in order to avoid significant thermal heating due to the stored beam. These magnets can be opened for backup and will be completely CEM shielded. Their pulsed power supplies will be built based on solid-state HV switches, even for short half-sine pulses generation.  
 
WEPC139 Recent Experience in the Fabrication and Brazing of Ceramic Beam Tubes for Kicker Magnets at FNAL vacuum, booster, controls, background 2335
 
  • C. R. Ader, C. C. Jensen, R. E. Reilly, D. Snee, J. H. Wilson
    Fermilab, Batavia, Illinois
  Ceramic beam tubes are utilized in numerous kicker magnets in different accelerator rings at Fermi National Accelerator Laboratory. Kovar flanges are brazed onto each beam tube end, since kovar and high alumina ceramic have similar expansion curves. The tube, kovar flange, end piece, and braze foil (titanium/inconel) alloy brazing material are stacked in the furnace and then brazed in the furnace at 1000°C. The ceramic specified is Alumina 99.8% Al2O3, a strong recrystalized high-alumina fabricated by slip casting. Recent experience at Fermilab with the fabrication and brazing of these tubes has brought to light numerous problems including tube breakage and cracking and also the difficulty of brazing the tube to produce a leak-tight joint. These problems may be due to the ceramic quality, voids in the ceramic, thinness of the wall, and micro-cracks in the ends which make it difficult to braze because it cannot fill tiny surface cracks which are caused by grain pullout during the cutting process. Solutions which are being investigated include lapping the ends of the tubes before brazing to eliminate the micro-cracks and also metallization of the tubes.  
 
WEPC142 Design of Pulsed Magnets for the Taiwan Photon Source septum, vacuum, storage-ring, injection 2341
 
  • C.-H. Chang, C. K. Chan, J.-R. Chen, C.-S. Fann, M.-H. Huang, C.-S. Hwang, F.-Y. Lin, Y.-H. Liu, C.-S. Yang
    NSRRC, Hsinchu
  A new Taiwan Photon source requires a high stability pulsed magnets for the top-up mode injection operation. We present a preliminary design of the pulsed magnets used for injection into the 3 GeV storage ring. A 0.6 m long kicker magnet prototype is fabricated for testing the field performance. The field testing results are described in this work. The septum magnet with a 0.4 mm thickness stainless steel vacuum chamber is real tested at 3 Hz operation. The field performance, the stray fields and the eddy current effect are presented in this paper.  
 
WEPC150 Fast Local Bump System for Helicity Switching at the Photon Factory undulator, photon, vacuum, alignment 2356
 
  • K. Harada, Y. Kobayashi, T. Miyajima, S. Nagahashi, T. Obina
    KEK, Ibaraki
  • S. Matsuba
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima
  Two APPLE-II type variably polarizing undulators will be installed at the south straight section of the PF (Photon Factory) ring. The 10Hz fast orbit switching in these undulators will be conducted for the helicity switching. The required angular difference of the orbits in two undulators is 0.3mrad. The five identical bump magnets and AC power supplies are manufactured to make 10Hz time varying local bumps. In order to achieve the local bump and prevent the fluctuation of the beam orbit with the effects of the insertion devices and magnetic errors, the feed forward correction with the bump magnets and the feedback correction with the fast steering magnets are required. In this presentation, the measurement results of the magnetic field and the frequency response, the configuration of the control system, and the simulation results to achieve the local bumps are shown.  
 
WEPP041 High-current Effects in the PEP-II Storage Rings vacuum, feedback, impedance, ion 2611
 
  • U. Wienands, W. X. Cheng, W. S. Colocho, S. DeBarger, F.-J. Decker, S. Ecklund, A. S. Fisher, D. Kharakh, A. Krasnykh, A. Novokhatski, M. K. Sullivan
    SLAC, Menlo Park, California
  High beam currents, 2A(HER) & 3A(LER), in PEP-II has been a challenge for the vacuum system. For the ~1 cm long bunches peak currents reach 50 A. Thus modest impedances can give rise to voltage spikes and discharges. A weakness was uncovered during Run 6: rf seals at the "flex flanges" that join the HER arc dipole and quadrupole chambers became a source of an increasing number of HER beam aborts. Vacuum activity was seen and thermal sensors on these flanges saw temperature spikes. Inspection of the seals found arcing and melting, prompting us to replace all of these seals with an improved design using Inconel instead of GlidCop fingers. We believe the GlidCop fingers do not maintain elasticity and hence can not follow chamber motion due to thermal effects. The Run 7 startup confirmed the success of this repair. However, high bunch current in the LER caused breakdown in a LER kicker. This limited the LER bunch current to about 1 mA. Inspection revealed damage to one of the recently added Macor pins that help support the electrodes. Failure analysis revealed heating of the pin & post-facto modeling shows high fields coming from a combination of HOM impedance and high peak currents.  
 
WEPP059 Automatic Post-operational Checks for the LHC Beam Dump System dumping, extraction, diagnostics, controls 2653
 
  • E. Gallet, J. Axensalva, V. Baggiolini, E. Carlier, B. Goddard, V. Kain, M. Lamont, N. Magnin, J. A. Uythoven, H. Verhagen
    CERN, Geneva
  In order to ensure the required level of reliability of the LHC beam dump system a series of internal post-operational checks after each dump action must be performed. Several data handling and data analysis systems are required internally and at different levels of the LHC control system. This paper describes the data acquisition and analysis systems deployed for post-operational checks, and describes the experience from the commissioning of the equipment where these systems were used to analyse the dump kicker performance.  
 
WEPP060 Abort Gap Cleaning Using the Transverse Feedback System: Simulation and Measurements in the SPS for the LHC Beam Dump System simulation, octupole, feedback, proton 2656
 
  • A. Koschik, B. Goddard, W. Höfle, G. Kotzian, D. K. Kramer, T. Kramer
    CERN, Geneva
  The critical and delicate process of dumping the beams of the LHC requires very low particle densities within the 3 microseconds of the dump kicker rising edge. High beam population in this so-called 'abort gap' might cause magnet quenches or even damage. Constant refilling due to diffusion processes is expected which will be counter-acted by an active abort gap cleaning system employing the transverse feedback kickers. In order to assess the feasibility and performance of such an abort gap cleaning system, simulations and measurements with beam in the SPS have been performed. Here we report on the results of these studies.  
 
WEPP061 A Position Monitor for the Aborted Beam in KEKB septum, diagnostics, electron, beam-losses 2659
 
  • N. Iida, M. Kikuchi, T. Mimashi, K. Mori, M. Tejima
    KEK, Ibaraki
  The beams in the KEKB rings are aborted by abort kickers, Lambertson septums and dumps. First the beams are kicked by the abort kickers rapidly in the horizontal direction to outside the beam pipe and are bent slowly in the vertical direction. At the same time horizontal magnetic fields shake the beam to protect the abort window where the kicked beam passes and protect the window from heat by the high current beam. A beam position monitor is installed in front of the dump. We can get some informations of aborted beam by the monitor. In this paper a method for monitoring the beam in the high energy ring at KEKB is described.  
 
WEPP063 R-matrices of the Fast Beam Extraction Section of AGS extraction, quadrupole, synchrotron, optics 2662
 
  • N. Tsoupas, L. Ahrens, J. W. Glenn, W. W. MacKay, T. Satogata
    BNL, Upton, Long Island, New York
  The Fast Beam Extraction (FEB) system of the Alternating Gradient synchrotron (AGS) extracts the beam bunches from AGS into the AGS-to-RHIC (AtR) beam transfer line, and the extracted bunches are injected into the Relativistic Heavy Ion Collider (RHIC) synchrotron. In a particular section of the beam extraction line the beam bunches are transported through the fringe field region of three main AGS magnets. Optical characteristics of this section change with trajectory and momentum. Therefore the calculation of the R-matrices in this part of the extraction line requires special attention. To describe accurately the R-matrices, the magnetic field of the AGS main magnets was measured on the median plane of the AGS magnet in both, the circulating beam region and the fringe field region, where the extracted beam is transported. Using these magnetic field maps we describe the procedure we use to calculate the R-matrices at the beam extraction region. These R-matrices are used to calculate the beam parameters at the starting point of the AtR beam transfer line and the required quadrupole settings to match to RHIC’s acceptance.  
 
WEPP064 Apertures in the LHC Beam Dump System and Beam Losses during Beam Abort extraction, simulation, vacuum, dumping 2665
 
  • T. Kramer, B. Goddard, M. Gyr, A. Koschik, J. A. Uythoven, Th. Weiler
    CERN, Geneva
  The LHC beam dump system is used to dispose accelerated protons and ions in a wide energy range from 450 GeV up to 7 TeV. An abort gap of 3 microseconds is foreseen to avoid sweeping particles through the ring aperture. This paper gives a brief overview of the critical apertures in the extraction region and the two beam dump lines, and presents MAD-X tracking studies made to investigate the impact of particles swept through the aperture due to extraction kicker failures or spurious particles within the abort gap.  
 
WEPP066 Results from the LHC Beam Dump Reliability Run dumping, vacuum, extraction, injection 2671
 
  • J. A. Uythoven, A. Antoine, E. Carlier, F. Castronuovo, L. Ducimetière, E. Gallet, B. Goddard, N. Magnin, H. Verhagen
    CERN, Geneva
  The LHC Beam Dumping System is one of the vital elements of the LHC Machine Protection System and has to operate reliably every time a beam dump request is made. Detailed dependability calculations have been made, resulting in expected rates for the different system failure modes. A 'reliability run' of the system, installed in its final configuration in the LHC, has been made to discover infant mortality problems and to compare the occurrence of the measured failure modes with their calculations.  
 
WEPP072 Evaluation of Beam Losses and Energy Deposition for A Possible Phase II Design for LHC Collimation simulation, beam-losses, collimation, proton 2686
 
  • L. Lari, R. W. Assmann, C. Bracco, M. Brugger, F. Cerutti, A. Ferrari, M. Mauri, S. Redaelli, L. Sarchiapone, V. Vlachoudis, Th. Weiler
    CERN, Geneva
  • J. E. Doyle, L. Keller, S. A. Lundgren, T. W. Markiewicz, J. C. Smith
    SLAC, Menlo Park, California
  • L. Lari
    EPFL, Lausanne
  The LHC beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.  
 
WEPP102 Design of the ILC RTML Extraction Lines extraction, collimation, damping, focusing 2752
 
  • S. Seletskiy, P. Tenenbaum, D. R. Walz
    SLAC, Menlo Park, California
  • N. Solyak
    Fermilab, Batavia, Illinois
  The Damping Ring to the Main Linac beamline (RTML) is equipped with three extraction lines (EL). Each EL can be used both for an emergency abort dumping of the beam and the tune-up continual train-by-train extraction. Two of the extraction lines are located downstream of the first and second stages of the RTML bunch compressor, and must accept both compressed and uncompressed beam with energy spread of 2.5 % and 0.15 % respectively. In this paper we report optical design that allowed us to minimize the length of the extraction lines while offsetting the beam dumps from the main line by the distance required for acceptable radiation level in the service tunnel. Proposed extraction lines can accommodate beams with different energy spreads at the same time providing the beam size suitable for the aluminum dump window.  
 
THPC073 Measurement of Resonance Driving Terms in the ATF Damping Ring resonance, coupling, sextupole, simulation 3155
 
  • R. Tomas, F. Zimmermann
    CERN, Geneva
  • K. Kubo, S. Kuroda, T. Naito, T. Okugi, J. Urakawa
    KEK, Ibaraki
  The measurement of resonance driving terms in the Damping Ring of the Accelerator Test Facility in KEK could help finding possible machine imperfections and even to optimize single particle stability through the minimization of non-linearities. The first experimental attempts of this enterprise are reported in this note.  
 
THPC114 Design and Performance of a Prototype Digital Feedback System for the International Linear Collider Interaction Point feedback, linear-collider, collider, extraction 3245
 
  • P. Burrows, B. Constance, H. Dabiri Khah, J. Resta-López
    JAI, Oxford
  • R. Apsimon, P. Burrows, C. I. Clarke, A. F. Hartin, C. Perry, C. Swinson
    OXFORDphysics, Oxford, Oxon
  • G. B. Christian
    ATOMKI, Debrecen
  • A. Kalinin
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  We present the design and preliminary results of a prototype beam-based digital feedback system for the Interaction Point of the International Linear Collider. A custom analogue front-end processor, FPGA-based digital signal processing board, and kicker drive amplifier have been designed, built, and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The system was measured to have a base latency of approximately 140 ns, increasing to approximately 148 ns with the inclusion of real-time charge normalisation.  
 
THPC117 Measurements and Analysis of Beam Transfer Functions in the Fermilab Recycler Ring Using the Transverse Digital Damper System diagnostics, feedback, pick-up, antiproton 3254
 
  • N. Eddy, J. L. Crisp, M. Hu
    Fermilab, Batavia, Illinois
  The Fermilab Recycler Ring Transverse Digital Damper System was designed to facilitate Beam Transfer Function measurements using a Network Analyzer connected to auxiliary system ports for timing and diagnostic purposes. The Digital Damper System has the capability for both open and closed loop measurements. The Beam Transfer Function measurements provide direct measurements of the machine impedance, beam stability, and beam parameters such as betatron tune and chromaticity. An overview of the technique is presented along with analysis and results from open and closed loop measurements in the Fermilab Recycler Ring.  
 
THPC121 LHC Transverse Feedback System and its Hardware Commissioning feedback, injection, vacuum, damping 3266
 
  • W. Höfle, P. Baudrenghien, F. Killing, Y. A. Kojevnikov, G. Kotzian, R. Louwerse, E. Montesinos, V. Rossi, M. Schokker, E. Thepenier, D. Valuch
    CERN, Geneva
  • E. V. Gorbachev, N. I. Lebedev, A. A. Makarov, S. Rubtsun, V. Zhabitsky
    JINR, Dubna, Moscow Region
  A powerful transverse feedback system ('damper') has been installed in LHC. It will stabilise coupled bunch instabilities in a frequency range from 3 kHz to 20 MHz and at the same time damp injection oscillations originating from steering errors and injection kicker ripple. The transverse damper can also be used as an exciter for purposes of abort gap cleaning or tune measurement. The power and low-level systems layout are described along with results from the hardware commissioning. The achieved performance is compared with earlier predictions and requirements for injection damping and instability control. Requirements and first measurements of the performance of the low-level system are summarized. The chosen approach for the low-level system using advanced FPGA technology is very flexible allowing implementation of future upgrades of the signal processing without changing the hardware.  
 
THPC122 Digital Signal Processing for the Multi-bunch LHC Transverse Feedback System pick-up, feedback, betatron, damping 3269
 
  • W. Höfle, P. Baudrenghien, G. Kotzian, V. Rossi
    CERN, Geneva
  For the LHC a VME card has been developed that contains all functionalities for transverse damping, diagnostics and controlled bunch by bunch excitation. It receives the normalized bunch by bunch position from two pick-ups via Gigabit Serial Links (SERDES). A Stratix II FPGA is responsible for resynchronising the two data streams to the bunch-synchronous clock domain (40.08 MHz) and then applying all the digital signal processing: In addition to the classic functionalities (gain balance, rejection of closed orbit, pick-up combinations, one-turn delay) it contains 3-turn Hilbert filters for phase adjustment with a single pick-up scheme, a phase equalizer to correct for the non-linear phase response of the power amplifier and an interpolator to double the processing frequency followed by a low-pass filter to precisely control the bandwidth. Using two clock domains in the FPGA the phase of the feedback loop can be adjusted with a resolution of 10 ps. Built-in diagnostic memory (observation and post-mortem) and excitation memory for setting-up are also included. The card receives functions to continuously adjust its parameters as required during injection, ramping and physics.  
 
THPC123 The PSI DSP Carrier (PDC) Board - a Digital Back-end for Bunch-to-bunch and Global Orbit Feedbacks in Linear Accelerators and Storage Rings feedback, controls, storage-ring, undulator 3272
 
  • B. Keil, R. Kramert, G. Marinkovic, P. Pollet, M. Roggli
    PSI, Villigen
  PSI has developed a signal processing VXS/VME64x board for accelerator applications like low-latency bunch-to-bunch feedbacks, global orbit feedbacks or low-level RF systems. The board is a joint development of PSI/SLS staff and staff working on the contribution of PSI for the European X-ray FEL (E-XFEL). Future applications of the board include the Intra-Bunchtrain Feedback (IBFB) of the E-XFEL as well as the upgrade of the SLS Fast Orbit Feedback (FOFB) and Multibunch Feedback (MBFB). The PDC board has four Virtex-4 FPGAs, two TS201 Tiger Sharc DSPs, VXS and VME64x 2eSST interfaces, and two front panel SFP multi-gigabit fibre optic links. Two 500-pin LVDS/multi-gigabit mezzanine connectors allow to interface the FPGAs to two application-dependent mezzanine modules each containing e.g. four 500 Msps 12-bit ADCs and two 14-bit DACs for the IBFB and MBFB, or four multi-gigabit SFP fibre optic transceivers for the FOFB. This paper reports on hardware and firmware concepts, system topologies and synergies of future applications.  
 
THPC124 The Manufacturing and Tests of The New Vertical Feedback Stripline at Soleil feedback, impedance, vacuum, simulation 3275
 
  • C. Mariette, J.-C. Denard, R. Nagaoka
    SOLEIL, Gif-sur-Yvette
  This paper describes the development of the kicker striplines for the bunch-by-bunch transverse instability feedback system at Soleil. A careful design of the striplines and of their vacuum feedthroughs was aimed at maximizing the effectiveness of the excitation power and minimizing the power taken from the beam. The excitation effectiveness improves with the shunt impedance. But, simultaneously, the beam impedance should be made as small as possible. We also found useful to estimate the temperature of the feedthroughs at high beam currents, especially on the ceramic-to-metal seals. We also report on the difficulties encountered with obtaining good feedthroughs.  
 
THPC127 Filling of High Current Singlet and Train of Low Bunch Current in SPring-8 Storage Ring feedback, injection, betatron, damping 3284
 
  • T. Nakamura, T. Fujita, K. Fukami, K. Kobayashi, C. Mitsuda, M. Oishi, S. Sasaki, M. Shoji, K. Soutome, M. Takao, Y. Taniuchi
    JASRI/SPring-8, Hyogo-ken
  • T. Ohshima
    RIKEN/SPring-8, Hyogo
  • Z. R. Zhou
    USTC/NSRL, Hefei, Anhui
  We performed the storage of high current singlet of 10mA/bunch and a train of bunches of 0.3mA/bunch under the bunch by bunch feedback systems with newly developed bunch current sensitive automatic attenuators with FPGA. The automatic attenuator reduces the signal level of the high current bunch by factor three to five to avoid the saturation of the feedback systems. With this system, the feedback systems suppress horizontal and vertical mode-coupling instabilities and raise the bunch current limit from 3.5mA/bunch to 12mA/bunch, and simultaneously the systems suppress the multi-bunch instabilities by resistive-wall and cavity higher order mode impedances. The improvement of the automatic attenuation system to fit to the final target of the bunch current in the train, 0.06mA/bunch, are being performed. The other problems which limit the filling patterns, such as saturation of the readout electronics of the beam position monitor system and the heating of vacuum components by high current bunches, will be briefly presented.  
 
THPC132 Bunch by bunch Transverse Feedback Development at ESRF feedback, damping, storage-ring, ion 3297
 
  • E. Plouviez, P. Arnoux, F. Epaud, J. M. Koch, G. A. Naylor, F. Uberto
    ESRF, Grenoble
  This paper describes the bunch by bunch transverse feedback implemented at ESRF. The first motivation of this project was to be able to cope with the constraint of the future operation of the ESRF with a stored current increased from 200mA to 300mA with a uniform or quasi uniform filling, but we were also interested in possible improvement of the operation with others filling patterns (16 and 4 bunches patterns for instance). Our system uses a classical scheme: The signal coming from a set of button type electrodes is demodulated in a homodyne RF front end and processed in a FPGA DSP to derive a correction signal which is applied to the beam with a wide band stripline kicker. Depending on the filling pattern of the storage ring (uniform filling or filling with a small number of high charge bunches), different kind of transverse instabilities have been observed in the past, due to the resistive wall impedance, ion trapping or mode coupling. We have tested the effect of our system in these different situation and report also the results of these tests.  
 
THPC133 Layout and Simulations of the FONT System at ATF2 extraction, simulation, feedback, pick-up 3300
 
  • J. Resta-López, P. Burrows
    JAI, Oxford
  We describe the adaptation of a Feedback On Nano-second Timescales (FONT) system for the final focus test beam line ATF2 at KEK. This system is located in the ATF2 extraction line, and is mainly conceived for cancellation of transverse jitter positions originated in the damping ring and by the extraction kickers. This jitter correction is performed by means of a combination of feed-forward (FF) and fast-feedback (FB) beam stabilisation. We define optimal positions for the kicker and BPM pairs of the FONT FF/FB system, and estimate the required kicker performance and BPM resolutions. Moreover simulation results are presented.  
 
THPC136 Design and Commissioning of a Bunch by Bunch Feedback System for the Australian Synchrotron feedback, damping, synchrotron, storage-ring 3306
 
  • M. J. Spencer, G. LeBlanc, K. Zingre
    ASP, Clayton, Victoria
  A transverse bunch feedback system has been designed in order to fight the effects of coupled bunch instabilities. This system is currently in the commissioning phase. A digital system was chosen because of its flexibility and diagnostic potential. While the major components were sourced from a private company, time has also been spent on in house development of an analogue front-end and the diagnostic components of the software.  
 
THPC138 Bunch-by-Bunch Online Diagnostics at HLS feedback, diagnostics, injection, storage-ring 3309
 
  • J. H. Wang, Y. B. Chen, L. J. Huang, W. Li, L. Liu, M. Meng, B. Sun, L. Wang, Y. L. Yang, Z. R. Zhou
    USTC/NSRL, Hefei, Anhui
  The design goal for the bunch-by-bunch analogue transverse feedback system at the Hefei Light Source (HLS) is to cure the transverse coupled bunch instabilities. The prototype implemented bunch-by-bunch feedback in 2006. Then we changed the circuit and replaced some components by ones of higher performance in order to get better effect. Diagnostic techniques are important tools to determine instabilities and to confirm the performance of the feedback systems. In addition to transverse feedback this system can provide online beam diagnostics and analysis in transverse and longitudinal directions. The diagnostic functions can record the response of every bunch while the feedback system manipulates the beam. The experimental results are presented.  
 
THPP002 EMMA RF Cavity Design and Prototype Testing at Daresbury impedance, acceleration, vacuum, electron 3374
 
  • C. D. Beard, P. A. Corlett, D. M. Dykes, P. Goudket, C. Hill, P. A. McIntosh, A. J. Moss, J. F. Orrett, J. H.P. Rogers, A. E. Wheelhouse, E. Wooldridge
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • N. Bliss
    STFC/DL, Daresbury, Warrington, Cheshire
  • A. E. Bogle, T. L. Grimm, A. A. Kolka
    Niowave, Inc., Lansing, Michigan
  At PAC’07 we discussed the design of a prototype cavity to be used on EMMA*. EMMA is a prototype non-scalling FFAG. It will contain 19 RF cavities operating at 1.3 GHz with a baseline accelerating voltage of 120 kV. A prototype cavity has been manufactured by Niowave, Inc. and we will present a discussion of its RF and mechanical design. This cavity was put through low power tests, to determine frequency, tuning range, shunt impedance and Q of the cavity; and high power tests, to confirm power handling ability, when it arrived at Daresbury Laboratory this spring. The results of these tests were compared to the simulations and a bead pull was carried out to obtain the field profile. The cavities for EMMA are likely to be powered by IOTs, these will be used for the high power tests, which will demonstrate cavity operation to the required maximum of 180 kV.

*E. Wooldridge et al. "RF Cavity Development for FFAG Application on ERLP at Daresbury," Proceedings of PAC’07, Albuquerque, NM (2007).

 
 
THPP004 EMMA - the World's First Non-scaling FFAG extraction, acceleration, injection, diagnostics 3380
 
  • T. R. Edgecock
    STFC/RAL, Chilton, Didcot, Oxon
  • C. D. Beard, J. A. Clarke, C. Hill, S. P. Jamison, A. Kalinin, K. B. Marinov, N. Marks, P. A. McIntosh, B. D. Muratori, H. L. Owen, Y. M. Saveliev, B. J.A. Shepherd, R. J. Smith, S. L. Smith, S. I. Tzenov, E. Wooldridge
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • J. S. Berg, D. Trbojevic
    BNL, Upton, Long Island, New York
  • N. Bliss, C. J. White
    STFC/DL, Daresbury, Warrington, Cheshire
  • M. K. Craddock
    UBC & TRIUMF, Vancouver, British Columbia
  • J. L. Crisp, C. Johnstone
    Fermilab, Batavia, Illinois
  • Y. Giboudot
    Brunel University, Middlesex
  • E. Keil
    CERN, Geneva
  • D. J. Kelliher, S. Machida
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  • S. R. Koscielniak
    TRIUMF, Vancouver
  • F. Meot
    CEA, Gif-sur-Yvette
  • T. Yokoi
    OXFORDphysics, Oxford, Oxon
  EMMA - the Electron Model of Many Applications - is to be built at the STFC Daresbury Laboratory in the UK and will be the first non-scaling FFAG ever constructed. EMMA will be used to demonstrate the principle of this type of accelerator and study their features in detail. The design of the machine and its hardware components are now far advanced and construction is due for completion in summer 2009.  
 
THPP009 Injection and Extraction Orbits and Twiss Parameters for the EMMA Ring injection, extraction, betatron, focusing 3395
 
  • B. D. Muratori, S. L. Smith, S. I. Tzenov
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Using the FFEMMAG code, the injection and extraction orbits for the EMMA ring at a variety of injection and extraction energies together with the Twiss parameters to be used for matching have been calculated. The orbits include two kickers together with a septum at both injection and extraction. The FFEMMAG code has been used in conjunction with several scripts so as to be able to scan the parameter space of the two kicker strengths for a section of the EMMA ring. The results confirm the choice of magnet and vacuum pipe apertures as being adequate to operate EMMA from 10 to 20 MeV.  
 
THPP046 Applicability of Stochastic Cooling in Small Electrostatic Storage Rings pick-up, ion, storage-ring, electron 3464
 
  • H. Danared
    MSL, Stockholm
  Several small electrostatic storage rings have been built or are being built for experiments in atomic and molecular physics. One example is the DESIREE double electrostatic storage ring* under construction at the Manne Siegbahn Laboratory. At the KEK electrostatic storage ring, electron cooling of 20 keV protons has been demostrated**. For heavy molecules, however, including bio-molecules, electron-cooling times are unrealistically long because of the low ion velocity and the correspondingly low electron energy which results in very small electron currents. For this reason, electron cooling is not foreseen for DESIREE. The rates of stochastic cooling, on the other hand, are at first glance unrelated to beam energy. Furthermore, the low particle numbers expected for many heavy molecules seem to make stochastic cooling attractive, theoretical rates being inversely proportional to particle numbers. In this paper, the rates of stochastic cooling for slow heavy particles are investigated with respect to, mainly, the bandwidths and signal strengths that can be expected at the low particle velocieties that are of interest at, e.g., DESIREE, and some numerical examples are presented.

* P. Löfgren et al., these proceedings
** E. Syresin, K. Noda and T. Tanabe, Proc. EPAC 2004, p. 162

 
 
THPP048 Experimental Demonstration of Longitudinal Ion Beam Accumulation with Electron Cooling injection, electron, ion, bunching 3470
 
  • C. Dimopoulou, B. Franzke, T. Katayama, F. Nolden, G. Schreiber, M. Steck
    GSI, Darmstadt
  • D. Möhl
    CERN, Geneva
  Recently, two longitudinal beam compression schemes have been successfully tested in the Experimental Storage Ring (ESR) at GSI with a beam of bare Ar ions at 65 MeV/u injected from the ion synchrotron SIS18. The first employs Barrier Bucket pulses, the second makes use of multiple injections around the unstable fixed point of a sinusoidal RF bucket at h=1. In both cases continuous electron cooling maintains the stack and merges it with the freshly injected bunch *. Using the beam diagnostic devices in the ring both stacking processes were demonstrated under the same conditions. The dependence of the accumulation performance on the available rf potential, the electron cooling strength as well as on the synchronization conditions between injection kicker pulse and rf wave was investigated. These experimental results provide the proof of principle for the planned fast stacking of Rare Isotope Beams aiming at high luminosities in the New Experimental Storage Ring ** of the FAIR project ***.

* C. Dimopoulou et al., JACoW Proceedings of COOL07, Bad Kreuznach,2007.
** C. Dimopoulou et al., PRST-AB 10 (2007) 020101.
*** FAIR Baseline Technical Report,www.gsi.de/fair/.

 
 
THPP070 Status of Center for Accelerator and Beam Applied Science of Kyushu University extraction, proton, cyclotron, septum 3521
 
  • Y. Yonemura, H. Arima, N. Ikeda, K. Ishibashi, H. Ishikawa, K. Maehata, T. Okai, N. Shigyo, Y. Uozumi, G. Wakabayashi
    Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
  • S. Fukumoto, Y. Kimura, H. Nakayama, A. Takagi
    KEK, Ibaraki
  • Y. Mori
    KURRI, Osaka
  • T. Noro, K. Sagara
    Kyushu University, Fukuoka
  • T. Tomimasu
    SAGA, Tosu
  A new accelerator facility of Center for Accelerator and Beam Applied Science is under construction on Ito Campus to promote research and education activities at Kyushu University. The facility consists mainly of a 10 MeV proton cyclotron as an injector and a 150 MeV Fixed Field Alternating Gradient (FFAG) accelerator, which was developed at KEK as a prototype of proton FFAG for various applications. In this paper, the status of the development of devices and the facility is described.  
 
THPP073 Performance of the SNS Front End and Warm Linac linac, target, beam-losses, radiation 3530
 
  • A. V. Aleksandrov, C. K. Allen, S. M. Cousineau, V. V. Danilov, J. Galambos, J. A. Holmes, D.-O. Jeon, T. A. Pelaia, M. A. Plum, A. P. Shishlo, M. P. Stockli, Y. Zhang
    ORNL, Oak Ridge, Tennessee
  The Spallation Neutron Source accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of an H- injector, capable of producing one-ms-long pulses at 60 Hz repetition rate with 38 mA peak current, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The 2.5 MeV beam from the Front End is accelerated to 86 MeV in the Drift Tube Linac, then to 185 MeV in a Coupled-Cavity Linac and finally to 1 GeV in the Superconducting Linac. With the completion of beam commissioning, the accelerator complex began operation in June 2006 and beam power is being gradually ramped up toward the design goal. Operational experience with the injector and linac will be presented including chopper performance, longitudinal beam dynamics study, and the results of a beam loss study.  
 
THPP074 Optimal Design of a High Current MEBT with Chopper emittance, target, focusing, beam-transport 3533
 
  • A. V. Aleksandrov
    ORNL, Oak Ridge, Tennessee
  Many existing and proposed projects require a certain temporal structure imposed on the beam pulse, e.g., creating gaps for low-loss extraction from a circular accelerator. Usually it is achieved using chopper systems. In order to reduce average beam power on the target and simplify kicker requirements chopper system is located in a lower energy part of the accelerator, typically in the medium energy transport line (MEBT) between the RFQ and the linac. Many of the MEBT layouts, proposed and in use, look very much alike and try to achieve a compromise between two opposing requirements of providing strong transverse focusing and sufficiently long empty drifts for the kickers. As a result, both requirements are not fully satisfied leading to space charge induced emittance increase and very challenging technical specifications for the kicker and its power supply. These difficulties quickly increase with the beam current. We propose a different MEBT layout, which does not compromise quality of beam transport and allows space for a kicker with any reasonable parameters. A generic design of a 5.5m long MEBT transporting 100mA with emittance increase of less than 5% is shown as an example.  
 
THPP087 4 GeV H- Charge Exchange Injection into the PS2 injection, septum, emittance, proton 3566
 
  • B. Goddard, W. Bartmann, M. Benedikt, A. Koschik, T. Kramer
    CERN, Geneva
  The proposed PS2 will accelerate protons from 4 to 50 GeV. The required beam intensity and brightness can only be achieved with a multi-turn H- charge exchange injection system, where the small emittance injected beam is used to paint the transverse phase space of the PS2 machine. This paper describes the constraints and conceptual design of the H- injection system and its incorporation into the present PS2 lattice. The requirements for the special injection system elements are described, in particular the injection chicane and painting magnet systems and the charge exchange foil. Some key performance aspects are investigated, including the stripping efficiency, expected emittance growth and beam loss arising from the simulated number of multiple foil traversals, together with estimates of foil heating.  
 
THPP088 Design Considerations for the PS2 Beam Dumps injection, extraction, simulation, shielding 3569
 
  • T. Kramer, M. Benedikt, B. Goddard, H. Vincke
    CERN, Geneva
  Studies have been made to evaluate and differentiate necessary beam disposal functions for the proposed PS2 accelerator. The paper describes briefly the different beam dump functionalities required for the PS2 machine and its transfer lines, and makes some first estimates about the expected beam loads. This data has been taken as input for comparing the different technical options for the dump systems, in particular to simulate the radiological impact of different internal or external beam dump concepts. The numbers derived have been used to help in evaluating the feasibility of the technical alternatives.  
 
THPP091 One Nano-second Bunch Compressor for High Intense Proton Beam dipole, proton, linac, target 3578
 
  • L. P. Chau, M. Droba, N. S. Joshi, O. Meusel, U. Ratzinger, C. Wiesner
    IAP, Frankfurt am Main
  About ten bunches of 2MeV proton rf-linac with an average current of 150mA at 175 MHz will be deflected by kicker on different paths into a magnetic bending system. Passing this optimized geometry they approach each other longitudinaly (βλ = 0.114m) and arrive at the same time at the focus of the dipole system. For longitudinal focussing of the merged bunches a rebuncher cavity is included in the bending system. The motivation and the layout of the whole project, "Frankfurter Neutronen Quelle am Stern-Gerlach Zentrum" (FRANZ), were presented in details in previous conferences*,**. More accurate investigation results in a revision of the preliminary concept. For a theoretical proof of principle one trajectory with the biggest path length of a new geometry is calculated by a multi particle beam dynamics program (LORASR). Preliminary investigations showed, that magnetic fringing fields and bunch-bunch interactions have to be included as detailed as posible in the beam simulations. In this paper the beam dynamics results from LORASR-simulations, the new geometry and the code development for the bunch compressor are discussed in details.

*L. P. Chau et al. Proc. of the Eur. Part. Acc. Conf., Edinburgh (2006), 1690-1692.
**O. Meusel et al. Proc. of the Lin. Acc. Conf., Knoxville (2006), MOPO51, 159-161.

 
 
THPP097 Commissioning Results of the Kicker Magnet in J-PARC RCS extraction, power-supply, proton, impedance 3590
 
  • J. Kamiya, M. Kinsho, M. Kuramochi, T. Takayanagi, T. Togashi, T. Ueno, M. Watanabe, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  Installation of the kickers in the extraction section of the RCS in J-PARC facility was completed. And they succeeded to extract the 3GeV proton beams in the first beam test. The operation parameters of the kickers agreed well with the parameters which were estimated from the magnetic field measurement and the current test of the power supplys. In this report, we summarized the results of the excitation test and the commissioning of the kicker magnet. The results of the magnetic field measurement showed the good uniformity in the wide range of the aperture. The characteristic feature of each kicker power supply was also measured precisely. Although the rise time and jitter of the output pulse have some minor variation due to the different characteristics of the thyratrons, the degree of variation was acceptably small. Combining the results of the magnetic field measurements, the relation between the charging voltage and the magnetic field was obtained for each kicker. The accelerated beam was successfully extracted at the operation parameters which were obtained from the relationship. The measurements result which was obtained by using the beam is also reported.  
 
THPP103 Design of the Beam Extraction System of the New Heavy Ion Synchrotrons SIS100 and SIS300 at FAIR extraction, septum, quadrupole, sextupole 3605
 
  • N. Pyka, U. B. Blell, P. J. Spiller, J. Stadlmann
    GSI, Darmstadt
  The proton and heavy ion synchrotrons SIS100 and SIS300 are the heart of the new FAIR facility which is under construction on the site of the present GSI. All ions from protons to uranium will be accelerated up to a magnetic rigidity of 100 Tm and 300 Tm, respectively. The design of the beam extraction system of both synchrotrons is completed and will be presented in this paper. The extraction devices of both synchrotrons are situated in one common straight section and deflect the beam vertically. SIS100 has been optimized for fast extraction by means of a distributed fast bipolar kicker system. However, slow extraction over a few seconds is also foreseen. SIS300 has been optimized for slow extraction and may generate spills of up to 100s. The slow extraction channel combines horizontal deflection by an electrostatic septum in the first stage with vertical deflection by a Lambertson septum magnet and subsequent magnetic extraction septa in the second stage. An emergency beam dumping system could be integrated in the extraction system of both machines.  
 
THPP105 Beam Commissioning Results of the RCS Injection and Extraction at J-PARC injection, extraction, emittance, septum 3611
 
  • P. K. Saha, N. Hayashi, H. Hotchi, F. Noda, Y. Shobuda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • H. Harada
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima
  • Y. Irie
    KEK, Ibaraki
  The beam commissioning of J-PARC (Japan Proton Accelerator Research Complex) 3 GeV RCS (Rapid Cycling Synchrotron) has been started from the end of year 2007. As injection is in the very first stage, an accurate and well controlled beam at the injection strongly related to the other part of the RCS commissioning, including extraction where, an well extracted beam directly reflects the overall commissioning result. In this paper, the beam commissioning results of the RCS injection and extraction will be reported.  
 
THPP111 A 250 kHz Chopper for Low Energy High Intensity Proton Beams proton, simulation, rfq, septum 3623
 
  • C. Wiesner, L. P. Chau, M. Droba, O. Meusel, U. Ratzinger
    IAP, Frankfurt am Main
  A neutron pulse with 1 ns pulse length and a repetition rate of 250 kHz is needed for the experiments on nuclear astrophysics using the Frankfurter Neutron source at the Stern-Gerlach-Zentrum. The time structure of the neutron flux is given by the primary proton beam witch hits a 7Li target. The creation of the required time structure on an intense proton beam of 200 mA dc with respect to emittance growth and beam losses is demanding. The pulsing of the ion source depends on the rise time of the plasma whereas the pulsing of the extraction voltage leads into high power deposition into the multi aperture extraction system. On the other hand a chopper system downstream of the RFQ results in rf power consumption due to beam loading and the problem of beam dumping at a beam power of several kW. Therefore it is planed to install a chopper as part of a resonant circuit in the LEBT – section consisting of four solenoids. Two different methods, magnetic and electric deflection, will be discussed with respect to emittance growth, beam losses and the influence on space charge compensation processes. Numerical simulations and preliminary results of experiments will be presented and compared.  
 
THPP113 Emittance Growth at LHC Injection from SPS and LHC Kicker Ripple injection, emittance, damping, feedback 3629
 
  • B. Goddard, M. J. Barnes, L. Ducimetière, W. Höfle, G. Kotzian
    CERN, Geneva
  Fast pulsed kicker magnets are used to extract beams from the SPS and inject them into the LHC. The kickers exhibit time-varying structure in the pulse shape which translates into small offsets with respect to the closed orbit at LHC injection. The LHC damper systems will be used to damp out the resulting betatron oscillations, to keep the growth in the transverse emittance within specification. This paper describes the results of the measurements of the kicker ripple for the two systems, both in the laboratory and with beam, and presents the simulated performance of the transverse damper in terms of beam emittance growth. The implications for LHC operation are discussed.  
 
FRXBGM01 Impedance Computation and Measurement in Modern Storage Rings impedance, storage-ring, simulation, single-bunch 3728
 
  • R. Nagaoka
    SOLEIL, Gif-sur-Yvette
  Recent progress in the evaluation of machine impedance and instability thresholds will be reviewed, and comparisons made between measurements and predicted impedance in recently commissioned storage rings.  
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