Fast cooling of antiproton and radioactive ion beams in future storage rings at GSI

Key issues of the new accelerator facility proposed for GSI are production, fast cooling, and accumulation of intense secondary beams, antiprotons and rare isotopes (RI). Single primary bunches of 2×1013 protons at 29 GeV and 1×1012 U28+-ions at 1 GeV/u shall be delivered from the new, fast-ramped 100 Tm-synchrotron SIS100. A large acceptance, reversible polarity collector ring is foreseen for fast RF debunching followed by fast stochastic pre-cooling in all phase planes. The envisaged total pre-cooling times are 4–5 s for antiprotons at 3 GeV and 0.5–1 s for fully stripped RI at 740 MeV/u. A separate accumulator ring RESR is provided for stochastic accumulation of antiprotons. The RI beams are transferred to a new experimental storage Ring NESR, where electron cooling (EC) is applied simultaneously to internal target and electron–ion collision experiments. For experiments with antiprotons, a special 50 Tm storage ring HESR shall be equipped with internal target and EC up to 15 GeV, optionally also with stochastic beam halo cooling. A maximum luminosity of 2×1032 cm−2s−1 and an energy resolution of about 100 keV at lower luminosity are main objectives of the HESR concept. Basic issues for the design of the storage ring complex are discussed.