Relativistic heavy ions: experiments in progress and planned at the Bevalac of Berkeley

The Superhilac-Bevatron linking at the Bevalac of Berkeley accelerates heavy ions up to energies of 200-2500 MeV per nucleon. The study of heavy ion collisions has introduced two concepts: the discrimination between peripheral and central collisions, and the kinematic representation of the inclusive cross sections of particle production, by means of contour-lines of the invariant cross section in the plane of the two dimensionless variables y and ν (y is the fragment rapidity, ν the ratio of the transverse moment with regards to the fragment mass). As for peripheral collisions, measurements dealt with the fragmentation at 00 of C, N, O, Ne and Ar ions (from 1.05 up to 2.1 GeV/nucleon), and the fragmentation of the light ions Be, C, Cu, Pb (400, 1050, and 2100 MeV/nucleon) with pion production. As for central collisions the studies were concerned with: the fragmentation and particle production in the streamer chamber, the heavy fragment production with high energy neutrons, the production of light particles a 1800, or pion multiple production from 3.5 to 15.20, the production of fragments at high transverse momentum, and of pions low energy. The construction of a new spectrometer HISS (Heavy Ion Spectrometer System) is predicted