Electron Cooling for Future High-energy Hadron Accelerators

Electron cooling is an important method to reduce the emittance and momentum spread of hadron beams, and it has been successfully applied in several facilities around the world. In 2019, the world¿s first RF-based electron cooler (LEReC) was commissioned at BNL for the RHIC BES-II project, and the integrated luminosity of RHIC is finally doubled. In addition, electron cooling is also a must for the future Electron-Ion Collider (BNL EIC). However, the high energy requirement of the electron beam (150 MeV) is far beyond what all present coolers can achieve (4.3 MeV). For that, an electron ring cooler with strong radiation damping is proposed and designed, in which the non-magnetized and dispersive cooling techniques are applied. In this talk, I will introduce the experimental and simulation results of the two facilities. Mainly, I will introduce several new phenomena that were first observed in LEReC, such as the beam heating effect and the ion beam focusing effect. Besides, some new theories that were developed for the ring cooler will also be discussed.