Presently the electron cooling of ions in GeV energy range is a substantial part of a number of modern projects. The Tevatron luminosity upgrade program includes the electron cooling of 9 GeV antiprotons in the Recycler ring to compensate the beam heating during stacking process. Electron cooling of protons at energy of 2.5 GeV can be used for luminosity support of the COSY ring in experiments with internal target. MEEC 98 was the forth workshop on Medium Energy Electron Cooling. Substantial part of the reports was dedicated to new possible concepts of the cooling system.
New conditions require new concepts.
Only in the electron beam energy range less than 5 MeV the DC acceleration in an electrostatic device of the electron beam immersed in the longitudinal magnetic field can be used. To reduce the average electron beam power the scheme with electron beam circulating in additional ring can be used. In combination with longitudinal magnetic field and betatron acceleration of the electrons such a scheme has potentially minimal cost. To cool the bunched ion beam at energy 10 GeV and higher the use of bunched electron beam looks very attractive. Electron beam quality is determined not only by the generation scheme, but by the ion beam parameters, which are to be stabilized.