Beam diagnostics based on time-domain bunch-by-bunch data

Abstract

. A bunch-by-bunch longitudinal feedback system has been used to control coupledbunch longitudinal motion and study the behavior of the beam at ALS, SPEAR, PEP-II, and DAFNE. Each of these machines presents unique challenges to feedback control of unstable motion and data analysis. Here we present techniques developed to adapt this feedback system to operating conditions at these accelerators. A diverse array of techniques has been developed to extract information on different aspects of beam behavior from the time-domain data captured by the feedback system. These include measurements of growth and damping rates of coupledbunch modes, bunch-by-bunch current monitoring, measurements of bunch-by-bunch synchronous phases and longitudinal tunes, and beam noise spectra. A technique is presented which uses the longitudinal feedback system to measure transverse growth and damping rates. Techniques are illustrated with data acquired at all of the four above-mentioned machines. INTRODUCTION A...