Speaker
Description
For demonstrating the beam focusing scheme required for linear colliders, the Accelerator Test Facility (ATF) at KEK is designed to focus an electron beam to 37 nm vertical size at the virtual interaction point (IP) utilizing the low emittance beam (vertical emittance: 12~pm.rad) generated in the damping ring. Because of the special focusing beam optics, even small angle changes of beam particles in the beamline can cause significant distortions at IP. The transverse wakefield effects have been observed as beam size growth depending on the beam intensity at ATF. In this report, we describe the wakefield affection on the beam size at IP with pulse-by-pulse beam orbit fluctuations. Simulation and experiments in the final focus beam line of ATF, which have confirmed the effect, are also reported.
