Commissioning and performance of low impedance electrostatic separators for high luminosity at CESR

Electrostatic separators have been used extensively for a number of years in colliding beam storage rings because of their ability to generate closed orbits displacements which are of opposite sign depending on the charge of the stored beams. As higher beam currents became more in demand, it was realized that separators could provide a means of multiplying the maximum beam current without needing to build a second ring to avoid unwanted collisions that additional bunches would make. Much higher beam currents have resulted and have in turn placed new demands on the separator performance. To this end four new horizontal separators were designed and installed in CESR at Cornell in the fall of 1995. As of the end of 1998 they have operated with beams of up to 300 mA per beam. Next year they will be required to work at 500 mA per beam. This paper reviews their performance, especially under high current conditions