Author: Chao, A.
Paper Title Page
MOPS006 Beam Tilt due to Transverse Wakefields for DAΦNE, SuperB, KEKB and SuperKEKB 601
 
  • D.M. Zhou, K. Ohmi
    KEK, Ibaraki, Japan
  • A. Chao
    SLAC, Menlo Park, California, USA
 
  When a beam bunch traverses a transverse impedance, the bunch head generates a transverse wakefield that kicks the bunch tail, generating a betatron motion of the tail relative to the head. In a storage ring, in a steady state, this kick to the bunch tail produces a transverse closed orbit (e.g. in the y-direction) of the bunch tail relative to the bunch head, which means the beam now has a y-z tilt. Such beam tilt due to transverse wakefields may cause a loss of luminosity in storage ring colliders or loss of brightness in light sources. In this paper, we present a preliminary study of the beam tilt effect for the colliders DAΦNE, SuperB, KEKB and SuperKEKB.  
 
MOPS086 Beam Breakup Simulation for the PEP-X ERL 805
 
  • Y. Jiao, Y. Cai, A. Chao
    SLAC, Menlo Park, California, USA
 
  Funding: The work is supported by the U.S. Department of Energy under contract No. DE-AC02-76SF00515.
The transverse beam breakup (BBU) is one of the dominant factors in ERL for the available beam current. A tracking code built in Matlab is developed and benchmarked by comparing with the analytical solutions with the simple model. Study on the threshold current and emittance growth due to the transverse BBU for PEP-X ERL are presented in this paper.
 
 
WEPC045 Transverse Emittance Reduction with Tapered Foil 2112
 
  • Y. Jiao, Y. Cai, A. Chao
    SLAC, Menlo Park, California, USA
 
  Funding: The work is supported by the U.S. Department of Energy under contract No. DE-AC02-76SF00515.
The idea of reducing transverse emittance with tapered energy-loss foil is proposed by J.M. Peterson in 1980s and recently by B. Carlsten. In present paper, we present the physical model of tapered energy-loss foil and analyze the emittance reduction using the concept of eigen emittance. The study shows that, to reduce transverse emittance, one should collimate at least 4% of particles which has either much low energy or large transverse divergence. The multiple coulomb scattering is not trivial, leading to a limited emittance reduction ratio.
 
 
WEPC105 Multiparticle Simulation of Intrabeam Scattering for SuperB 2259
 
  • T. Demma, M.E. Biagini, M. Boscolo
    INFN/LNF, Frascati (Roma), Italy
  • K.L.F. Bane, A. Chao, M.T.F. Pivi
    SLAC, Menlo Park, California, USA
 
  Intrabeam scattering (IBS) is associated with multiple small angle scattering events leading to emittance growth. In most electron storage rings, the growth rates arising from IBS are much longer than damping times due to synchrotron radiation, and the effect on emittance growth is negligible. However, IBS growth rates increase with increasing bunch charge density, and for storage rings such as SuperB, that operate with high bunch charges and very low vertical emittance, the IBS growth rates can be large enough to produce significant emittance increase. Several formalisms have been developed for calculating IBS growth rates in storage rings*. However these models, based on Gaussian bunch distributions, cannot investigate some interesting aspects of IBS such as its evolution during the damping process and its effect on the beam distribution. We developed a multiparticle tracking code, based on the Binary Collision Model**, to investigate these effects. In this communication we present the structure of the code and simulation results obtained with particular reference to the SuperB parameters. Simulation results are compared with those of conventional IBS theories.
* A. Piwinski, Lect. Notes Phys. 296 (1988); J.D. Bjorken and S.K. Mtingwa, Part. Accel. 13 (1983); K. Kubo et al., Phys. Rev. ST-AB 8 (2005).
** Peicheng Yu et al., Phys. Rev. ST–AB 12 (2009).
 
 
THPZ003 The SuperB Project: Accelerator Status and R&D 3684
 
  • M.E. Biagini, S. Bini, R. Boni, M. Boscolo, B. Buonomo, T. Demma, E. Di Pasquale, A. Drago, L.G. Foggetta, S. Guiducci, S.M. Liuzzo, G. Mazzitelli, L. Pellegrino, M.A. Preger, P. Raimondi, U. Rotundo, C. Sanelli, M. Serio, A. Stecchi, A. Stella, S. Tomassini, M. Zobov
    INFN/LNF, Frascati (Roma), Italy
  • M.A. Baylac, O. Bourrion, J.-M. De Conto, N. Monseu, C. Vescovi
    LPSC, Grenoble, France
  • K.J. Bertsche, A. Brachmann, Y. Cai, A. Chao, M.H. Donald, R.C. Field, A.S. Fisher, D. Kharakh, A. Krasnykh, K.C. Moffeit, Y. Nosochkov, A. Novokhatski, M.T.F. Pivi, J.T. Seeman, M.K. Sullivan, S.P. Weathersby, A.W. Weidemann, U. Wienands, W. Wittmer, G. Yocky
    SLAC, Menlo Park, California, USA
  • S. Bettoni
    PSI, Villigen, Switzerland
  • A.V. Bogomyagkov, I. Koop, E.B. Levichev, S.A. Nikitin, I.N. Okunev, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin, P. Vobly
    BINP SB RAS, Novosibirsk, Russia
  • B. Bolzon, M. Esposito
    CERN, Geneva, Switzerland
  • F. Bosi
    INFN-Pisa, Pisa, Italy
  • L. Brunetti, A. Jeremie
    IN2P3-LAPP, Annecy-le-Vieux, France
  • A. Chancé
    CEA, Gif-sur-Yvette, France
  • P. Fabbricatore, S. Farinon, R. Musenich
    INFN Genova, Genova, Italy
  • E. Paoloni
    University of Pisa and INFN, Pisa, Italy
  • C. Rimbault, A. Variola
    LAL, Orsay, France
  • Y. Zhang
    IHEP Beijing, Beijing, People's Republic of China
 
  The SuperB collider project has been recently approved by the Italian Government as part of the National Research Plan. SuperB is a high luminosity (1036 cm-2 s-1) asymmetric e+e collider at the Y(4S) energy. The design is based on a “large Piwinski angle and Crab Waist” scheme already successfully tested at the DAΦNE Phi-Factory in Frascati, Italy. The project combines the challenges of high luminosity colliders and state-of-the-art synchrotron light sources, with two beams (e+ at 6.7 and e- at 4.2 GeV) with extremely low emittances and small beam sizes at the Interaction Point. As unique features, the electron beam will be longitudinally polarized at the IP and the rings will be able to ramp down to collide at the tau/charm energy threshold with one tenth the luminosity. The relatively low beam currents (about 2 A) will allow for low running (power) costs compared to similar machines. The insertion of beam lines for synchrotron radiation users is the latest feature included in the design. The lattice has been recently modified to accommodate insertion devices for X-rays production. A status of the project and a description of R&D in progress will be presented.