Simulation of Bunch Precompression at High Currents in the Slc Damping Rings

In the Stanford Linear Collider (SLC) each beam, after leaving a damping ring, is compressed in the Ring-to-Linac (RTL) transfer line before entering the linear accelerator. At a bunch population of 4:0 10 particles, due to the limited energy acceptance of the RTL, approximately 15% of the beam has normally been lost. During the 1996 run, however, to eliminate this loss the bunch was partially precompressed in the damping ring, just before extraction; the beam loss in the RTL was reduced to almost zero. In Ref. (1) the operation and performance of precompression are presented. Also given is an analysis which, however, does not include the e ects of the longitudinal wake eld on the beam dynamics. In this report we extend that analysis to include these e ects. Presented at 1997 Particle Accelerator Conference Vancouver, British Columbia, Canada May 12{16, 1997 Work supported by Department of Energy contract DE{AC03{76SF00515. M. Minty, et al, \Operation and Performance of Bunch Precompression for Increased Current Transmission at the SLC," these proceedings. SIMULATION OF BUNCH PRECOMPRESSION AT HIGH CURRENTS IN THE SLC DAMPING RINGS K.L.F. Bane, M.G. Minty, A.W. Chao, SLAC, Stanford, CA 94309, USA