First Experiences with HESR Stochastic Cooling System

The stochastic cooling system of the HESR (High Energy Storage Ring) is based on completely new structures especially designed for the HESR. Each beam surrounding slot of these so called slot-ring couplers covers the whole image current without a reduction of the HESR aperture and without any plunging system. One pickup and one kicker have been already fabricated and installed into the COSY ring to demonstrate stochastic cooling in all three dimensions with only one structure. First results of commissioning with proton beams will be presented. The longitudinal cooling system at HESR is based on filter cooling with an optical notch-filter and ToF cooling. The demanding accuracy concerning phase stability requires dedicated control of the notch-frequency. The optical COSY filter has been modified and can be proven in long term runs together with the new stochastic cooling system.