Beam lifetimes in the ATF damping ring

Electron beam lifetimes in the Accelerator Test Facility (ATF) damping ring are limited by elastic and inelastic beam-gas scattering as well as the Touschek effect, which, due to intrabeam scattering, transfers transverse into longitudinal momentum exceeding the momentum acceptance of the machine, thus leading to particle loss. Since the Touschek effect depends strongly on the vertical beam size, it can be utilized to determine the vertical beam emittance, thus providing a cross-check for data obtained by different methods, e.g. using the synchrotron radiation monitor. First results of beam lifetime studies and estimates of the vertical emittance are presented. (author)