Beam Lifetime in the SLS Storage Ring

Three shifts in Nov. and Dec. 2001 were spent on beam lifetime measurements. Elastic gas scattering was measured by moving scrapers into the beam. Touschek lifetime was measured as function of single bunch current, RF voltage and tune. Analysis of Touschek lifetime provided information on the energy acceptance and its limitation due to a sextupolar resonance, and on the value of emittance coupling. Indications for turbulent bunch lengthening were found and evaluated to estimate the longitudinal broad band impedance.