Latest news from stochastic cooling developments for the collector ring at FAIR

The CR stochastic cooling system aims at fast 3D cool- ing of antiprotons, rare isotopes and stable ions. Because of the large apertures and the high electronic gain, damp- ing within the 1-2 GHz band of the unwanted microwave modes propagating through the vacuum chambers is es- sential. It will be realised within the ultrahigh vacuum using resistively coated ceramic tubes and ferrites. The greatest challenge is increasing the signal to noise ratio for antiproton cooling by means of cryogenic movable (plunging) pickup electrodes, which follow the shrinking beam during cooling and then withdraw fast before the new injection. Linear motor drive units plunge synchro- nously the pickup electrodes on both sides of the ion beam (horizontal/vertical). Their technical concept is summarized. Their performance has been demonstrated in successive measurements inside testing chambers at GSI. Recent simulations of the critical antiproton cooling with the designed system are shown