Initial Cooling Experiments (ICE) at CERN

The Initial Cooling Experiment (ICE) has been a four-year study on the feasibility of high-energy proton-antiproton colliding beam experiments. It was realized that a cooling scheme aimed at increasing the phase-space density of the antiproton beam was essential for providing luminosities of the order of 10/sup 30/ cm/sup -2/ s/sup -1/ in the collider. Stochastic cooling of protons at about 2 GeV/c and electron cooling of protons at about 50 MeV kinetic energy were successfully tried in the ICE storage ring. During these tests it turned out that stochastic cooling alone would be sufficient to implement the 0.5 TeV c.m. collider of the CERN Super Proton Synchrotron (SPS). Besides physics at high energy, ICE opened up the road to antiproton physics at low (eventually very low) energies. This resulted in Project LEAR, now in the course of construction. It has been possible to cool, store, and stack antiprotons in ICE with a view to the determination of a lower limit on the antiproton lifetime. ICE has therefore been, in a modest way, the first antiproton facility. (25 refs).