Bunched beam stochastic cooling

A number of bunched-beam stochastic cooling experiments have recently been performed. The goal of these measurements was to evaluate the usefulness of stochastic cooling in collider storage rings. For the Relativistic Heavy Ion Collider project, bunched-beam momentum cooling is being considered to counteract the longitudinal emittance growth caused by intrabeam scattering. In addition, an operational system to cool the transverse emittances of colliding proton and antiproton bunches in the Fermilab Tevatron is presented in detail. In the Tevatron, luminosity lifetime is determined mostly by the transverse emittance growth rates. The known sources of growth are intrabeam scattering, beam-beam interaction, and external noise. In addition, due to misalignments during transfers and instabilities throughout the injector train, the initial luminosity is depressed by the enlarged emittance of the bunches. Assuming that the duration of collider stores is determined by the decay in luminosity, the cooling system will lengthen the optimum storage time. This provides more time for antiproton production (which occurs during the store), and hence generates higher initial luminosities.<>