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Papaphilippou, Y.

Paper Title Page
MOPC129 Lattice without Transition Energy for the Future PS2 370
 
  • D. Trbojevic, S. Peggs
    BNL, Upton, Long Island, New York
  • Y. Papaphilippou, R. de Maria
    CERN, Geneva
 
  The Large Hadron Collider (LHC) will be commissioned very soon. Improvements of the LHC injection complex are considered in the upgrade possibilities. In the injection complex it is considered that the aging Proton Synchrotron (PS) would be replaced with a new fast cycling synchrotron PS2. The energy range would be from 5-50 GeV with a repetition rate of 0.3 Hz. This is a report on the PS2 lattice design using the Flexible Momentum Compaction (FMC) method*. The design is trying to fulfill many requirements: high compaction factor, racetrack shape with two long zero dispersion straight sections, circumference fixed to a value of 1346 meters (CPS2=15/77 CPS), using normal conducting magnets and avoiding the transition energy.

*D. Trbojevic et al. ”Design Method for High Energy Accelerator Without Transition Energy”, EPAC 90, Nice, June 12-16 (1990) pp. 1536-1538.

 
MOPP049 Collective Effects in the CLIC Damping Rings 658
 
  • G. Rumolo, J. B. Jeanneret, Y. Papaphilippou, D. Quatraro
    CERN, Geneva
 
  The possible performance limitations coming from collective effects in the CLIC damping rings are the subject of this paper. In particular, the consequences of space charge, due to the very high beam brilliance, and of the resistive wall impedance, due to the locally very small beam pipe, are considered potentially dangerous in spite of the high beam energy. Hence, they have been studied in detail with the HEADTAIL code, which has been modified in order to take into account a finer lattice structure as well as multi-bunch effects of the resistive wall wake field. The study aims at setting the intensity thresholds determined by these phenomena.  
MOPP050 Electron Cloud Build Up and Instability in the CLIC Damping Rings 661
 
  • G. Rumolo, Y. Papaphilippou
    CERN, Geneva
  • W. Bruns
    WBFB, Berlin
 
  Electron cloud can be formed in the CLIC positron damping ring and cause intolerable tune shift and beam instability. 2D and 3D build up simulations with the Faktor2 code, developed at CERN, have been done to predict the cloud formation in the arcs and wigglers of the damping rings. HEADTAIL simulations have been used to study the effect of this electron cloud on the beam and assess the thresholds above which the electron cloud instability would set in.  
MOPP060 Parameter Scan for the CLIC Damping Rings 679
 
  • Y. Papaphilippou, H.-H. Braun, M. Korostelev
    CERN, Geneva
 
  Triggered by the RF frequency reduction of the CLIC main linac cavities, the damping ring parameters had to be reevaluated and the rings' performance adapted to the new luminosity requirements. In view of a staged approach for reaching the ultimate energy of the collider, the dependence of the rings output emittances under the influence of Intrabeam Scattering is evaluated with respect to different beam characteristics such as bunch population, beam energy, coupling and longitudinal beam characteristics.  
MOPP061 Non Linear Dynamics Study of the CLIC Damping Rings Using Sympletic Integrators 682
 
  • Y. Papaphilippou
    CERN, Geneva
  • Ch. Skokos
    IMCCE, Paris
 
  A class of symplectic integrators with positive steps (SABA2) is applied to investigate the non-linear dynamics of the CLIC damping rings. The detrimental effect of the chromaticity sextupoles is studied using frequency and diffusion maps and verified with MADX ptc dynamic aperture tracking. The reduction of the dynamic aperture for off-momentum particles is also investigated.  
MOPP062 Optics Design Considerations for the CLIC Pre-damping Rings 685
 
  • Y. Papaphilippou
    CERN, Geneva
  • F. Antoniou
    National Technical University of Athens, Zografou
 
  The CLIC pre-damping rings have to accommodate a large emittance beam, coming in particular from the positron source and reduce its size to low enough values for injection into the main damping rings. Linear lattice design options based on an analytical approach for theoretical minimum emittance cells are presented. In particular the parameterisation of the quadrupole strengths and optics functions with respect to the emittance and drift lengths is derived. Complementary considerations regarding constraints imposed by positron stacking and input momentum spread are also considered.  
THPC052 Beam Losses and Collimation Considerations for PS2 3098
 
  • J. Barranco, W. Bartmann, M. Benedikt, Y. Papaphilippou
    CERN, Geneva
 
  The high intensity beams with different emittances foreseen to be delivered by the PS2, an upgraded version of the actual CERN Proton Synchrotron, require strict control of beam losses in order to protect the machine components and enable their hands-on maintenance. Beam loss simulations based on dedicated numerical tools are undertaken for a variety of PS2 beams and for different loss mechanisms, along the whole accelerating cycle. In this respect, the design of a collimation system is presented and its performance is compared within different lattice options.