Progress toward high energy electron cooling

All electron cooling systems in operation to date can be classified as low energy systems. The electron beam kinetic energy in such a system is limited to about 0.6-1 MeV by the use of a conventional commercial Cockcroft-Walton high-voltage power supply. This, in turn, bounds the maximum ion kinetic energy, accessible for cooling with today´s standard technology, to about 2 GeV/nucleon (about a factor of 2-3 times higher than the electron systems in operation today). Electron cooling systems with kinetic energies above 1 MeV could provide economically justifiable improvements in the performance of many existing and proposed accelerator complexes, such as RHIC, Tevatron and HERA. This paper reviews the status of the development of the technology needed for high energy electron cooling