Low emittance electron beams for the RHIC electron cooler

Abstract

An electron cooler, based on an energy recovery linac (ERL) is under development for the relativistic heavy ion collider (RHIC) at Brookhaven National Laboratory. This will be the first electron cooler operating at high energy with bunched beams. In order to achieve sufficient cooling of the ion beams the electron have to have a charge of 5 nC and a normalized emittance less than 4 mu. This paper presents the progress in optimizing the injector and the emittance improvements from shaping the charge distribution in the bunch.