Measurements and simulations of electron-cloud-induced tune shifts and emittance growth at CesrTA

Extensive measurements of electron-cloud-induced be-tatron tune shifts and emittance growth are presented fortrains of positron and electron bunches at 2.1 and 5.3 GeV atvarious bunch populations. Measurements using a witnessbunch with variable distance from the end of the train andvariable bunch population inform the study of cloud decayand the pinch eect. Improved electron cloud buildup model-ing using detailed information on photoelectron productionproperties obtained from recently developed simulations suc-cessfully describes the tune shift measurements after deter-mining ring-wide secondary-yield properties of the vacuumchamber by fitting the model to data. Space-charge electricfield maps of the cloud from the validated model are thenincorporated into a multiparticle tracking simulation of thebeam through the lattice with electron cloud elements inthe dipoles and field-free regions. The simulations predictemittance growth in agreement with the measurements.