Fermilab, Batavia, Illinois
The more beam is cooled, the less stable it is. In the Recycler Ring, antiprotons are cooled both with stochastic and electron cooling. To stabilize it against the resistive wall instability, a digital damper is successfully used. Digital dampers can be described as linear operators with explicit time dependence, and that makes a principle difference with analogous dampers. Theoretical description of the digital dampers is presented. Electron cooling makes possible a two-beam instability of the cooled beam with the electron beam. Special features of this instability are described, and the remedy is discussed.
BNL, Upton, Long Island, New York
Stochastic cooling of 100 GeV/nucleon bunched beams has been achieved in the Relativistic Heavy Ion Collider (RHIC). The physics and technology of the longitudinal cooling system are discussed, and plans for a transverse cooling system are outlined.