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  

Heifets, S. A.

Paper Title Page
FRPMS061 Impedance and Single Bunch Instability Calculations for the ILC Damping Rings 4141
  • K. L.F. Bane, S. A. Heifets, Z. Li, C.-K. Ng, A. Novokhatski, G. V. Stupakov, R. L. Warnock
    SLAC, Menlo Park, California
  • M. Venturini
    LBNL, Berkeley, California
  Funding: Work supported by US Department of Energy contract DE-AC02-76SF00515

One of the action items for the damping rings of the International Linear Collider (ILC) is to compute the broad-band impedance and, from it, the threshold to the microwave instability. For the ILC it is essential that the operating current be below threshold. Operating above threshold would mean that the longitudinal emittance of the beam would be increased. More seriously, above threshold there is the possibility of time dependent variation in beam properties (e.g. the "sawtooth" effect) that can greatly degrade collider performance. In this report, we present the status of our study including calculations of: an impedance budget, a pseudo-Green's function suitable for Haissinski equation and instability calculations, and instability calculations themselves.

FRPMS077 High Current Effects in the PEP-II SLAC B-factory 4225
  • A. Novokhatski, S. A. Heifets, D. Teytelman
    SLAC, Menlo Park, California
  Funding: Work supported by US DOE contract DE-AC02-76SF00515.

Wake fields defining beam stability affect also the beam optics and beam properties in high current machines. We present observations and analysis of the optical effects in the PEP-II SLAC B-factory, which has the record in achievement of high electron and positron currents. We study the synchronous phase and the bunch length variation along the train of bunches, overall bunch lengthening and effects of the wakes on the tune and on the Twiss parameters. This analysis is being used in upgrades of PEP II and may be applied to future B-factories and damping rings for Linear Colliders.