Electron and stochastic cooling at COSY

The synchrotron and storage ring COSY delivers proton beams with momenta between 300 and 3500 MeV/c for internal and external experiments. It is operating both with electron and stochastic cooling. The electron cooling is used mainly at the injection energy with 22 keV electrons to increase the intensity of the polarised proton beam with a combined cooling stacking injection. In addition, the electron-cooled proton beam is used for diagnostic purposes of machine parameters. The stochastic cooling for COSY is working in the proton momentum range between 1.5 and 3.5 GeV/c and is up to now only used for equilibrium experiments with thin internal targets and long flat top times. The longitudinal stochastic cooling system is extended by a fast frequency variable optical notchfilter to make use of a supercycle in COSY with from cycle to cycle varying flat top energies. The results of the electron cooling and stacking injection as well as the good results of the optical notchfilter for the stochastic cooling will be presented.