Study of turn-by-turn vertical beam dynamics at low and high energy cesr operation

Abstract

Presently, the Cornell Electron-Positron Storage Ring (CESR) is operated at two different beam energies: low energy (E=2GeV) for high energy physics (CESR-c), and high energy (E=5.3GeV) for synchrotron radiation production for the Cornell High Energy Synchrotron Source (CHESS). The electron and positron bunches' vertical dynamics at these two energies are vastly different, in part due to the change in the pretzel orbit, the presence of wiggler magnets at low energy, and synchrotron radiation power at two different energies. Using a 32 channel photomultiplier array and a beam position monitor (BPM), vertical beam dynamics were measured on a turn-by-turn basis during CHESS and CESR-c operation as well as dedicated machine studies time. For these studies, electron cloud effects such as vertical tune shift and vertical beam size blow-up along the electron and positron trains are quantified at these two vastly different beam energies.