Author: Schulte, D.
Paper Title Page
MOPPC073 Improvements in the PLACET Tracking Code 301
  • A. Latina, E. Adli, D. Schulte, J. Snuverink
    CERN, Geneva, Switzerland
  • B. Dalena
    CEA/IRFU, Gif-sur-Yvette, France
  The tracking code PLACET simulates beam transport and orbit corrections in linear accelerators. It incorporates single- and multi-bunch effects, static and dynamic imperfections. It has an interface based on both Tcl/Tk and Octave to provide maximum flexibility and easy programming of complex scenarios. Recently, new functionality has been added to expand its simulation and tuning capabilities, such as: tools to perform beam-based alignment of non-linear optical systems, possibility to track through the interaction region in presence of external magnetic fields (detector solenoid), higher order imperfections in magnets, better tools for integrated feedback loops. Moreover, self contained frameworks have been created to ease the simulation of CLIC Drive Beam, CLIC Main Beam, and other existing electron machines such as CTF3 and FACET.  
TUPPR024 CLIC Recombination Scheme for the Low Energy Operation Mode 1864
  • A. Gerbershagen, D. Schulte
    CERN, Geneva, Switzerland
  • P. Burrows
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  The CLIC recombination scheme is a concept of multiplication of the drive beam frequency in order to generate a 12 GHz RF wave for the main beam acceleration. CLIC is designed to be operated in nominal and in low energy modes. The low energy operation modes require the train length to be increased by different factors in order to maintain the same level of luminosity. Also the number of initial trains that are merged to form each final train is changed. The combination scheme must be able to accommodate and recombine both long and short trains for nominal and low energy CLIC operation modes. The recombination hence becomes a non-trivial process and makes the correction of the errors in the drive beam more challenging. The present paper describes in detail the recombination process and its consequences.  
TUPPR028 Recent Improvements in the Orbit Feedback and Ground Motion Mitigation Techniques for CLIC 1876
  • J. Snuverink, J. Pfingstner, D. Schulte
    CERN, Geneva, Switzerland
  The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques have been proposed - quadrupole stabilization and positioning, final doublet stabilization as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) that model the latest hardware designs have been performed. Furthermore, additional imperfections have been introduced and the robustness of this system is discussed in detail. The possibility of using ground motion measurements as an alternative to the quadrupole stabilization is investigated.  
TUPPR029 Performance of Linear Collider Beam-Based Alignment Algorithms at FACET 1879
  • A. Latina, J. Pfingstner, D. Schulte
    CERN, Geneva, Switzerland
  • E. Adli
    University of Oslo, Oslo, Norway
  The performance of future linear colliders will depend critically on beam-based alignment (BBA) and feedback systems, which will play a crucial role both in the linear and in the non-linear systems of such machines, e.g., the linac and the final-focus. Due to its characteristics, FACET is an ideal test-bench for BBA algorithms and linear collider beam-dynamics in general. We present the results of extensive computer simulations and their experimental verification.  
TUPPR034 Beam-based Alignment in CTF3 Test Beam Line 1894
  • G. Sterbini, S. Döbert, R.L. Lillestøl, E. Marín, D. Schulte
    CERN, Geneva, Switzerland
  • E. Adli
    University of Oslo, Oslo, Norway
  The CLIC linear collider is based on the two beams acceleration scheme. During acceleration, the drive beam suffers a large increase in its energy spread. In order to efficiently transport such a beam, beam-based alignment techniques together with tight pre-alignment tolerances are crucial. A beam-based steering campaign has been conducted at the Test Beam Line of the CLIC Test Facility to evaluate the performance of several algorithms. In the following we present and discuss the obtained results.  
TUPPR035 A Comparative Study for the CLIC Drive Beam Decelerator Optics 1897
  • G. Sterbini, D. Schulte
    CERN, Geneva, Switzerland
  • E. Adli
    University of Oslo, Oslo, Norway
  The baseline for the CLIC drive beam decelerators optics consists of a 2-m-long FODO cell. This solution was adopted to have strong focusing in order to mitigate the effect of the PETS wakefields and to minimize the drive beam envelope. Taking into account the most recent PETS design, we compare the performance of the baseline FODO cell with a proposal that consider twice longer FODO cell. Despite of the expected cost in term of performance, the reduction of the complexity of the system due to the halving of the number of quadrupoles can be beneficial for the overall optimization of the decelerator design.  
TUPPR039 Beam Dynamics Studies for the CLIC Main Linac 1903
  • I. Nesmiyan, R.M. Jones
    UMAN, Manchester, United Kingdom
  • A. Latina, D. Schulte
    CERN, Geneva, Switzerland
  Implications of the long-range wakefield on beam quality are investigated through a detailed beam dynamics study. Injection offsets are considered and the resulting emittance dilution recorded, including systematic and random sources of error. These simulations have been conducted for damped and detuned structures (DDS) and for waveguide damped structures–both for the CLIC collider.  
TUPPR060 Detection of Ground Motion Effects on the Beam Trajectory at ATF2 1954
  • Y. Renier, J. Pfingstner, D. Schulte, R. Tomás
    CERN, Geneva, Switzerland
  The ATF2 experiment is currently demonstrating the feasibility of the beam delivery system for the future linear collider. The tunning is very critical to obtain the nanometer vertical beam size at the interaction point and in the case of CLIC, ground motion effects on the beam must be corrected. In this respect, as a proof of principle of a ground motion feed forward, the ground motion effects on the beam trajectory are extracted from the beam position monitor readings.  
WEPPP066 Performance Simulations of a Phase Stabilization System Prototype for CTF3 2858
  • A. Gerbershagen, T. Persson, D. Schulte, P. Skowroński
    CERN, Geneva, Switzerland
  • P. Burrows, G.B. Christian
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • A. Gerbershagen, C. Perry
    JAI, Oxford, United Kingdom
  • E. Ikarios
    National Technical University of Athens, Athens, Greece
  The CLIC drive beam provides RF power for acceleration of the main beam, and hence the drive beam’s longitudinal phase tolerances are very tight. A feedforward chicane consisting of four electromagnetic kickers is proposed as a correction system for the phase errors, which should allow loosening of the tolerances. A prototype of such a chicane system, developed by CERN, INFN and the University of Oxford, is planned to be installed at CFT3 in 2012. The present paper summarizes the parameters of the planned phase correction system and presents simulations, which are used to make predictions of the performance of such a feedforward system at CTF3.  
TUPPC086 Conceptual Design of the CLIC damping rings 1368
  • Y. Papaphilippou, F. Antoniou, M.J. Barnes, S. Calatroni, P. Chiggiato, R. Corsini, A. Grudiev, J. Holma, T. Lefèvre, M. Martini, M. Modena, N. Mounet, A. Perin, Y. Renier, G. Rumolo, S. Russenschuck, H. Schmickler, D. Schoerling, D. Schulte, M. Taborelli, G. Vandoni, F. Zimmermann
    CERN, Geneva, Switzerland
  • C. Belver-Aguilar, A. Faus-Golfe
    IFIC, Valencia, Spain
  • A. Bernhard
    KIT, Karlsruhe, Germany
  • M.J. Boland
    ASCo, Clayton, Victoria, Australia
  • A.V. Bragin, E.B. Levichev, S.V. Sinyatkin, P. Vobly, K. Zolotarev
    BINP SB RAS, Novosibirsk, Russia
  • M. Korostelev
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • E. Koukovini
    EPFL, Lausanne, Switzerland
  • M.A. Palmer
    CLASSE, Ithaca, New York, USA
  • M.T.F. Pivi, S.R. Smith
    SLAC, Menlo Park, California, USA
  • R.P. Rassool, K.P. Wootton
    The University of Melbourne, Melbourne, Australia
  • L. Rinolfi
    JUAS, Archamps, France
  • A. Vivoli
    Fermilab, Batavia, USA
  The CLIC damping rings are designed to produce unprecedentedly low-emittances of 500 nm and 5 nm normalized at 2.86 GeV, in all beam dimensions with high bunch charge, necessary for the performance of the collider. The large beam brightness triggers a number of beam dynamics and technical challenges. Ring parameters such as energy, circumference, lattice, momentum compaction, bending and super-conducting wiggler fields are carefully chosen in order to provide the target emittances under the influence of intrabeam scattering but also reduce the impact of collective effects such as space-charge and coherent synchrotron radiation. Mitigation techniques for two stream instabilities have been identified and tested. The low vertical emittance is achieved by modern orbit and coupling correction techniques. Design considerations and plans for technical system, such as damping wigglers, transfer systems, vacuum, RF cavities, instrumentation and feedback are finally reviewed.  
WEPPR066 Effects of the External Wakefield from the CLIC PETS 3078
  • A. Latina, D. Schulte
    CERN, Geneva, Switzerland
  • J. Gao, Y. Wang
    IHEP, Beijing, People's Republic of China
  The CLIC main linac accelerating structures will be powered by the Power Extraction and Transfer Structure (PETS) located in the drive beam decelerators. Misalignments of the PETS will excite dipolar modes in the couplers of the main linac structures that will kick the beam leading to beam quality degradation. In this paper, the impact of such dipolar kicks is studied, and tolerances, based on analytical estimations, are found both in the single- and the multi-bunch regimes. Numerical simulation obtained using the tracking code PLACET are shown to confirm the analytical estimates.  
WEPPR067 Study of Fundamental Mode Multipolar Kicks in Double- and Single-feed Power Couplers for the CLIC Main Linac Accelerating Structure 3081
  • A. Latina, A. Grudiev, D. Schulte
    CERN, Geneva, Switzerland
  Multipolar kicks from the fundamental mode have been calculated in the CLIC baseline accelerating structure with double–feed input and output power couplers. The influence of such multipolar kicks on the main linac beam dynamics has been investigated. Furthermore, an alternative design of the couplers with single-feed has been studied and compared with the double-feed. Such an alternative would significantly simplify the waveguide system of the main linac but potentially introduce an harmful dipolar kick from the fundamental mode. The geometry of the coupler has been optimized in order to minimize such a dipolar kick and keep it below threshold levels determined with beam dynamics simulations. Influence of the higher order multipoles has been investigated as well and acceptable levels have been determined.  
WEPPR076 Positron Options for the Linac-ring LHeC 3108
  • F. Zimmermann, O.S. Brüning, Y. Papaphilippou, D. Schulte, P. Sievers
    CERN, Geneva, Switzerland
  • H.-H. Braun
    Paul Scherrer Institut, Villigen, Switzerland
  • E.V. Bulyak
    NSC/KIPT, Kharkov, Ukraine
  • M. Klein
    The University of Liverpool, Liverpool, United Kingdom
  • L. Rinolfi
    JUAS, Archamps, France
  • A. Variola, Z.F. Zomer
    LAL, Orsay, France
  • V. Yakimenko
    BNL, Upton, Long Island, New York, USA
  The full physics program of a future Large Hadron electron Collider (LHeC) requires both pe+ and pe- collisions. For a pulsed 140-GeV or an ERL-based 60-GeV Linac-Ring LHeC this implies a challenging rate of, respectively, about 1.8·1015 or 4.4·1016 e+/s at the collision point, which is about 300 or 7000 times the past SLC rate. We consider providing this e+ rate through a combination of measures: (1) Reducing the required production rate from the e+ target through colliding e+ (and the LHC protons) several times before deceleration, by reusing the e+ over several acceleration/deceleration cycles, and by cooling them, e.g., with a compact tri-ring scheme or a conventional damping ring in the SPS tunnel. (2) Using an advanced target, e.g., W-granules, rotating wheel, sliced-rod converter, or liquid metal jet, for converting gamma rays to e+. (3) Selecting the most powerful of several proposed gamma sources, namely Compton ERL, Compton storage ring, coherent pair production in a strong laser, or high-field undulator radiation from the high-energy lepton beam. We describe the various concepts, present example parameters, estimate the electrical power required, and mention open questions.