BNL, Upton, Long Island, New York, USA
There is a strong interest in running RHIC at low ion beam energies of 2.5-20GeV/nucleon; this is much lower than the typical operations with 100GeV/nucleon. The primary motivation for this effort is to explore the existence and location of the critical point on the QCD phase diagram. Electron cooling can increase the average integrated luminosity and increase the length of the stored lifetime. Simulations and conceptual cooling sub-system designs are underway. The present plan is to provide 10–50mA of bunched electron beam with adequate quality and an energy range of 0.9–5MeV. The preliminary cooling facility configuration planned to be fully inside the RHIC tunnel will include a 102.74MHz SRF gun, a booster cavity, a beam transport to the Blue ring to allow electron-ion co-propagation for ~10-20m, then a 180 degree u-turn electron transport so the same electron beam can similarly cool the Yellow ion beam, then to a dump. The electron beam instrumentation systems that will be described include current transformers, BPMs, profile monitors, a pepper pot emittance station and loss monitors.
