A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z    

Wolski, A.

Paper Title Page
TPPP035 Performance of the PEP-II B-Factory Collider at SLAC 2369
 
  • J. Seeman, J. Browne, Y. Cai, S. Colocho, F.-J. Decker, M.H. Donald, S. Ecklund, R.A. Erickson, A.S. Fisher, J.D. Fox, S.A. Heifets, R.H. Iverson, A. Kulikov, N. Li, A. Novokhatski, M.C. Ross, P. Schuh, T.J. Smith, K.G. Sonnad, M. Stanek, M.K. Sullivan, P. Tenenbaum, D. Teytelman, J.L. Turner, D. Van Winkle, M. Weaver, U. Wienands, M. Woodley, Y.T. Yan, G. Yocky
    SLAC, Menlo Park, California
  • M.E. Biagini
    INFN/LNF, Frascati (Roma)
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • C. Steier, A. Wolski
    LBNL, Berkeley, California
  • G. Wormser
    IPN, Orsay
  
  Funding: Work supported by DOE contract DE-AC02-76SF00515.

For the PEP-II Operation Staff: PEP-II is an asymmetric e+e- collider operating at the Upsilon 4S and has recently set several performance records. The luminosity has reached 9.2 x 1033/cm2/s. PEP-II has delivered an integrated luminosity of 710/pb in one day. It operates in continuous injection mode for both beams boosting the integrated luminosity. The peak positron current has reached 2.55 A in 1588 bunches. The total integrated luminosity since turn on in 1999 has reached 256/fb. This paper reviews the present performance issues of PEP-II and also the planned increase of luminosity in the near future to over 2 x 1034/cm2/s. Upgrade details and plans are discussed.

 
RPPP034 Multi-Stage Bunch Compressors for the International Linear Collider 2357
 
  • P. Tenenbaum, T.O. Raubenheimer
    SLAC, Menlo Park, California
  • A. Wolski
    LBNL, Berkeley, California
  
  We present bunch compressor designs for the International Linear Collider (ILC) which achieve a reduction in RMS bunch length from 6 mm to 0.3 mm via multiple stages of compression, with stages of acceleration inserted between the stages of compression. The key advantage of multi-stage compression is that the maximum RMS energy spread is reduced to approximately 1%, compared to over 3% for a single-stage design. Analytic and simulation studies of the multi-stage bunch compressors are presented, along with performance comparisons to a single-stage system. Parameters for extending the systems to a larger total compression factor are discussed.  
RPPP045 Single-Bunch Instability Driven by the Electron Cloud Effect in the Positron Damping Ring of the International Linear Collider 2884
 
  • M.T.F. Pivi, T.O. Raubenheimer
    SLAC, Menlo Park, California
  • A.F. Ghalam
    USC, Los Angeles, California
  • K.C. Harkay
    ANL, Argonne, Illinois
  • K. Ohmi
    KEK, Ibaraki
  • R. Wanzenberg
    DESY, Hamburg
  • A. Wolski
    LBNL, Berkeley, California
  • F. Zimmermann
    CERN, Geneva
  
  Funding: Work supported by the U.S. DOE under contracts DE-AC02-76SF00515.

With the recommendation that the future International Linear Collider (ILC) should be based on superconducting technology, there is considerable interest in exploring alternate designs for the damping rings (DR). The TESLA design was 17 km in circumference with a "dog-bone" configuration. Two other smaller designs have been proposed that are 6 km and 3 km in length. In the smaller rings, collective effects may impose the main limitations. In particular for the positron damping ring, an electron cloud may be produced by ionization of residual gas or photoelectrons and increase through the secondary emission process. The build-up and development of an electron cloud is more severe with the higher average beam current in the shorter designs. In this paper, we present recent computer simulation results for the electron cloud build-up and instability thresholds for the various DR configurations.

 
RPPP053 Simulations of Resistive-Wall Instability in the ILC Damping Rings 3241
 
  • A. Wolski, D.A. Bates, J.M. Byrd
    LBNL, Berkeley, California
  
  Funding: Work supported by U.S. Department of Energy, Director, Office of Science, Contract No. DE-AC03-76SF00098.

Options being considered for the ILC Damping Rings include lattices with circumferences up to 17 km. The circumference, beam current and beam energy place the damping rings in a regime where resistive-wall instability is a concern, particularly as there are very demanding tolerances on the bunch-to-bunch jitter. Generally, it is possible to make good analytical estimates of the coupled-bunch growth rates in a storage ring, but particular features of the damping rings (including the fill pattern, large variations of the lattice functions and beam-pipe cross-section in different parts of the ring, and transverse beam coupling in the long straight sections) make it desirable to study the coupled-bunch instabilities using simulations. Here, we present the results of simulations of the transverse instabilities using a detailed lattice model. A bunch-by-bunch feedback system will be needed to suppress the instabilities, and a model for an appropriate feedback system is included in the simulations.

 
RPPP054 Achieving Large Dynamic Aperture in the ILC Damping Rings 3277
 
  • A. Wolski
    LBNL, Berkeley, California
  • Y. Cai
    SLAC, Menlo Park, California
  
  Funding: Work supported by US Department of Energy, Director, Office of Science - Contract Nos. DE-AC03-76SF00098 and DE-AC03-76SF00515.

The Damping Rings for the International Linear Collider have challenging requirements for the acceptance, because of the high average injected beam power and the large beam produced from the positron source. At the same time, the luminosity goals of the collider mean that the natural emittance must be very small, and this makes it particularly difficult to achieve a good dynamic aperture. We describe a design approach and present a lattice design that meets the emittance specification and has a very promising dynamic aperture. We also discuss the potential impact of the damping wiggler and of magnet errors.

 
RPPT025 Beam Conditioning and FEL Studies Using MAD and Genesis
 
  • Y. Vinokurov, E. Esarey, G. Penn, A. Sessler, A. Wolski, J.S. Wurtele
    LBNL, Berkeley, California
  
  Funding: This work was supported by the Office of Science, High Energy Physics, U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

Beam conditioning using a variety of lattices is explored using MAD in conjunction with Genesis. In particular, the conditioning effects of a simple FODO lattice are simulated in MAD and the resulting particle distribution is then used as an input to Genesis to examine the effects of a conditioner on FEL performance. Studies of a plasma-based conditioner have been performed. In this scheme conventional RF accelerating cavities are replaced by a plasma accelerator. The wavelength of the plasma wave is typically shorter than the longitudinal bunch length, resulting in regions of conditioned and unconditioned beam. Studies were also performed analyzing the sensitivity of FEL performance to changes in various system parameters.