Planar Pick-Up Electrodes for Stochastic Cooling at the FAIR Project

The collector ring (CR) of the proposed facility for antiproton and ion research (FAIR) includes a fast stochastic cooling system for exotic nuclei with β = 0.83 and antiprotons with β = 0.97. For fast cooling, a good S/N ratio of the pick-up is crucial. The large initial emittances lead to the requirement of covering a large aperture (typically 200 mm). The λ/4-loop electrodes, currently used in the ESR, have a good coupling impedance to the beam, but also some disadvantages. The electrical connections are also the mechanical mountings, which leads to reliability problems. Another disadvantage is the inherent frequency and velocity dependence. For FAIR, a new planar pick-up for the frequency band from 1-2 GHz is developed.