FIRST INTERNAL AND EXTERNAL EXPERIMENTS AT COSY JUELICH

The inauguration of the cooler synchrotron COSY Julich was celebrated on April Ist, 1993. After the first successful acceleration to proton momenta above 800 GeV/c, beamtimes for experiments were scheduled in p arallel to further machine development. The first experiment was the i nternal target experiment EDDA, which investigated the energy dependen ce of the p-p interaction. It makes use of a 3 X 4 um(2) thin CH2 fibe r as an internal target. The thickness of the fiber is more than adequ ate to achieve high luminosities, so the intensity of the stored beam has to be reduced to 10(7) p. On the other hand, it is thin enough to achieve beam lifetimes of 3 s at 1.4 GeV/c. Details of the target fabr ication and the first experimental results will be discussed. Both ext ernal experimental facilities at COSY, the time-of-flight spectrometer , and the magnetic spectrometer BIG KARL use a liquid hydrogen (deuter ium) target. The first experiments were carried out at proton energies between 300 MeV and 500 MeV. Also, these experimental data will be pr esented. Two further internal experiments are prepared for the install ation into the COSY ring. The target for the first experiment is a gas -jet target, the second experiment uses ribbon targets for the interac tion. The status of both experimental setups will be shown.