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Chao, A.

Paper Title Page
FRPMS081 Geometric Effects on Electron Cloud 4243
 
  • L. Wang, A. Chao
    SLAC, Menlo Park, California
  • J. Wei
    BNL, Upton, Long Island, New York
  
  The development of an electron cloud in the vacuum chambers of high intensity positron and proton storage rings may limit the machine performances by inducing beam instabilities, beam emittance increase, beam loss, vacuum pressure increases and increased heat load on the vacuum chamber wall. The electron multipacting is a kind of geometric resonance phenomenon and thus is sensitive to the geometric parameters such as the aperture of the beam pipe, beam shape and beam bunch fill pattern, etc. This paper discusses the geometric effects on the electron cloud build-up in a beam chamber and examples are given for different beams and accelerators.  
FRPMS085 Transverse Effect due to Short-range Resistive Wall Wakefield 4267
 
  • J. Wu, A. Chao
    SLAC, Menlo Park, California
  • J. R. Delayen
    Jefferson Lab, Newport News, Virginia
  
  Funding: AWC and JW were supported by US DOE under contract No. DE-AC02-76SF00515. JRD was supported by US DOE under contract No. DE-AC05-84-ER40150 and No. DE-AC05-00-OR22725.

For accelerator projects with ultra short electron beam, beam dynamics study has to invoke the short-range wakefield. In this paper, we first obtain the short-range dipole mode resistive wall wakefield. Analytical approach is then developed to study the single bunch transverse beam dynamics due to this short-range resistive wall wake. The results are applied to the LCLS undulator and some other proposed accelerators.