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Raimondi, P.

 
Paper Title Page
MOPLS016 LHC IR Upgrade: A Dipole First Option with Local Chromaticity Correction 571
 
  • R. de Maria, O.S. Brüning
    CERN, Geneva
  • P. Raimondi
    INFN/LNF, Frascati (Roma)
  
  In the framework of the LHC Luminosity Upgrade, we develop a new layout of the interaction region (IR) with betastar equal to 25cm in which the combination-separation dipoles come first with respect to the triplet assembly (dipole first) in opposition of the nominal layout (quadrupole first). The new layout presents several advantages (separate channel for multipole errors, straightforward crossing angle scheme, early separation of the beam). The payoff is a large beta function in the triplet, which enhances the chromaticity and other non-linear effects. We investigate options for local chromaticity correction and their effects on long-term stability.  
MOPLS029 Preliminary Study of a Crab Crossing System for DAFNE 607
 
  • A. Gallo, D. Alesini, F. Marcellini, P. Raimondi, M. Zobov
    INFN/LNF, Frascati (Roma)
  
  The implementation of a crab crossing scheme at the Frascati Phi-factory DAFNE is under consideration, together with several other ideas and upgrades to increase the collider luminosity. The crab crossing is beneficial to the luminosity because it is expected to optimize the geometrical superposition of the colliding bunches and to weaken the synchro-betatron beam-beam resonances. The basic specifications of such a system, the expected luminosity increase, a preliminary design of the crab cavities and the architecture of the dedicated RF system are presented.  
MOPLS047 Design of an Asymmetric Super-B Factory 646
 
  • J. Seeman, Y. Cai, A. Novokhatski, A. Seryi, M.K. Sullivan, U. Wienands
    SLAC, Menlo Park, California
  • M.E. Biagini, P. Raimondi
    INFN/LNF, Frascati (Roma)
  
  Submitted for the High Luminosity Study Group for an Asymmetric Single-pass Super-B Factory: Parameters are being studied for a high luminosity e+e- collider operating at the Upsilon 4S that would deliver a luminosity of over 1036/cm2/s. This collider would use a novel combination of linear collider and storage ring techniques. In this scheme an electron beam and a positron beam are first stored in fast-damping and low-emittance damping rings, then extracted, accelerated, compressed and focused to the interaction point. After collision the two beams are decelerated and re-injected in the damping rings to be damped and extracted for collision again. The explored beam parameters are similar to those used in the design of the International Linear Collider, except for the beam energies. Design parameters for very flat beams and round beams have been studied.  
TUODFI02 DAFNE Experience with Negative Momentum Compaction 989
 
  • M. Zobov, D. Alesini, M.E. Biagini, A. Drago, A. Gallo, C. Milardi, P. Raimondi, B. Spataro, A. Stella
    INFN/LNF, Frascati (Roma)
  
  There are several potential advantages for a collider operation with a lattice having a negative momentum compaction factor (alfa): bunches can be shorter and have a more regular shape; longitudinal beam-beam effects and synchrobetatron resonances are predicted to be less dangerous; requirements on sextupole strengths can be relaxed because there is no head-tail instability with the negative chromaticity. Since the lattice of the Frascati e+e- Phi-factory DAFNE is flexible enough to provide collider operation with alfa < 0, we have exploited this possibility to study experimentally the beam dynamics. The negative momentum compaction lattices have been successfully implemented and stable 1 A currents have been stored in both the electron and positron rings without any problem for RF cavities and feedback systems operation. First collisions have been tested at low currents. In this paper we describe the experimental results and compare them with expectations and numerical simulations. Present limitations to DAFNE operation with alfa < 0 are also discussed.  
slides icon Transparencies
TUPLS009 Design and Tests of New Fast Kickers for the DAFNE Collider and the ILC Damping Rings 1502
 
  • D. Alesini, S. Guiducci, F. Marcellini, P. Raimondi
    INFN/LNF, Frascati (Roma)
  
  In this paper we illustrate the design of new, fast stripline kickers to inject or extract bunches in electron/positron rings. The kickers have been designed for the injection upgrade of the Phi-factory DAFNE and as injection/extraction devices for the International Linear Collider (ILC) damping rings. The design is based on tapering the striplines in order to simultaneously obtain low impedance and an excellent uniformity of the deflecting field. The design has been done using 2D and 3D electromagnetic codes such as Superfish and HFSS. High voltage test results on prototypes are also shown.  
THPCH011 Wire Compensation of Parasitic Crossings in DAFNE 2808
 
  • M. Zobov, D. Alesini, C. Milardi, M.A. Preger, P. Raimondi
    INFN/LNF, Frascati (Roma)
  • D.N. Shatilov
    BINP SB RAS, Novosibirsk
  
  Long-range beam-beam interactions (parasitic crossings) are one of the main luminosity performance limitations for the Frascati e+e- Phi-factory DAFNE. In particular, the parasitic crossings (PC) lead to a substantial lifetime reduction of both beams in collision. This puts a limit on the maximum storable current and, as a consequence, on achievable peak and integrated luminosity. In order to alleviate the problem numerical and experimental studies of the PC compensation with current-carrying wires have been performed at DAFNE. Two such wires have been installed at both ends of the KLOE interaction region. Switching on the wires in accordance with the numerical predictions, improvement in the lifetime of the "weak" beam (positrons) has been obtained at the maximum current of the "strong" one (electrons) without luminosity loss. In this paper we describe the PC effects in DAFNE, summarize the results of numerical simulations on the PC compensation with the wires and discuss the experimental measurements and observations.  
WEPLS060 CLIC Polarized Positron Source Based on Laser Compton Scattering 2520
 
  • F. Zimmermann, H.-H. Braun, M. Korostelev, L. Rinolfi, D. Schulte
    CERN, Geneva
  • S. Araki, Y. Higashi, Y. Honda, Y. Kurihara, M. Kuriki, T. Okugi, T. Omori, T. Taniguchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • X. Artru, R. Chehab, M. Chevallier
    IN2P3 IPNL, Villeurbanne
  • E.V. Bulyak, P. Gladkikh
    NSC/KIPT, Kharkov
  • M.K. Fukuda, K. Hirano, M. Takano
    NIRS, Chiba-shi
  • J. Gao
    IHEP Beijing, Beijing
  • S. Guiducci, P. Raimondi
    INFN/LNF, Frascati (Roma)
  • T. Hirose, K. Sakaue, M. Washio
    RISE, Tokyo
  • K. Moenig
    DESY Zeuthen, Zeuthen
  • H.D. Sato
    HU/AdSM, Higashi-Hiroshima
  • V. Soskov
    LPI, Moscow
  • V.M. Strakhovenko
    BINP SB RAS, Novosibirsk
  • T. Takahashi
    Hiroshima University, Higashi-Hiroshima
  • A. Tsunemi
    SHI, Tokyo
  • V. Variola, Z.F. Zomer
    LAL, Orsay
  
  We describe the possible layout and parameters of a polarized positron source for CLIC, where the positrons are produced from polarized gamma rays created by Compton scattering of a 1.3-GeV electron beam off a YAG laser. This scheme is very energy effective using high finesse laser cavities in conjunction with an electron storage ring. We point out the differences with respect to a similar system proposed for the ILC.  
MOPLS027 Beam-beam Simulations for a Single Pass SuperB-factory 601
 
  • M.E. Biagini
    INFN/LNF, Frascati (Roma)
  • P. Raimondi, J. Seeman
    SLAC, Menlo Park, California
  • D. Schulte
    CERN, Geneva
  
  A study of beam-beam collisions for an asymmetric single pass SuperB-Factory is presented*. In this scheme an electron and a positron beam are first stored and damped in two damping rings, then extracted, compressed and focused to the IP. After collision the two beams are re-injected in the DR to be damped and extracted for collision again. The explored beam parameters are similar to those used in the design of the International Linear Collider, except for the beam energies. Very flat beams and round beams were compared in the simulations, with the GuineaPig code**, in order to optimize both luminosity performances and beam blow-up after collision. With such approach, luminosities of the order of 1036 /(cm2 sec) can be achieved.

*http://arxiv.org/abs/physics/0512235.**D. Schulte. “Study of electromagnetic and hadronic background in the Interaction Region of the TESLA Collider”, PhD Thesis, Hamburg, 1996.

 
MOPLS052 Luminosity Improvement at PEP-II Based on Optics Model and Beam-beam Simulation 661
 
  • Y. Cai, W.S. Colocho, F.-J. Decker, Y. Nosochkov, P. Raimondi, J. Seeman, K.G. Sonnad, M.K. Sullivan, J.L. Turner, M. Weaver, U. Wienands, W. Wittmer, M. Woodley, Y.T. Yan, G. Yocky
    SLAC, Menlo Park, California
  
  The model independent analysis (MIA) has been successfully used at PEP-II to understand machine optics and improve the luminosity. However, the rate of success was limited because the improvement of optics does not necessarily lead to increase of luminosity. Recently, we were able to reconstruct MIA model in a full optics code, LEGO, and used it to calculate complete lattice and beam parameters. These parameters were fed to the beam-beam code, BBI, to understand the luminosity histories at PEP-II over the past year. Using these tools, we optimized the luminosity by varying the beam parameters such as emittance. Finally, we implemented an optimized solution with a set of asymmetric horizontal orbit bumps into the machines during a delivery shift with a few percentage gain in luminosity. The solution was retained at PEP-II machines along with the luminosity. Later, these asymmetric bumps also played a vital role in reaching 1x1034cm-2s-1 as the beam currents increased.  
MOPLS028 DAFNE Status Report 604
 
  • A. Gallo, D. Alesini, M.E. Biagini, C. Biscari, R. Boni, M. Boscolo, B. Buonomo, A. Clozza, G.O. Delle Monache, E. Di Pasquale, G. Di Pirro, A. Drago, A. Ghigo, S. Guiducci, M. Incurvati, P. Iorio, C. Ligi, F. Marcellini, C. Marchetti, G. Mazzitelli, C. Milardi, L. Pellegrino, M.A. Preger, L. Quintieri, R. Ricci, U. Rotundo, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, S. Tomassini, C. Vaccarezza, M. Vescovi, M. Zobov
    INFN/LNF, Frascati (Roma)
  • G. Benedetti
    CELLS, Bellaterra (Cerdanyola del Vallès)
  • L. Falbo
    INFN-Pisa, Pisa
  • J.D. Fox, P. Raimondi, D. Teytelman
    SLAC, Menlo Park, California
  • E. Levichev, S.A. Nikitin, P.A. Piminov, D.N. Shatilov
    BINP SB RAS, Novosibirsk
  
  The operation of DAFNE, the 1.02 GeV c.m. e+e- collider of the Frascati National Laboratory with the KLOE detector, started in April 2004 has been concluded at the end of March 2006 with a total delivered luminosity of 2 fb-1 on the peak of the Phi resonance, 0.2 fb-1 off peak and a high statistics scan of the resonance. The best performances of the collider during this run have been a peak luminosity of 1.5 1032 cm-2s-1 and a daily delivered luminosity of 10 pb-1. The KLOE detector has been removed from one of the two interaction regions and its low beta section substituted with a standard magnetic structure, allowing for an easy vertical separation of the beams, while the FINUDA detector has been moved onto the second interaction point. Several improvements on the rings have also been implemented and are described together with the results of machine studies aimed at improving the collider efficiency and testing new operating conditions.