A damping ring design for future linear colliders

The authors present a preliminary design of a damping ring for the TeV Linear Collider (TLC), a future linear collider with an energy of 1/2 to 1 TeV in the center of mass. Because of limits of the emittance, repetition rate, and longitudinal impedance, use is made of combined function FODO cells with wigglers in insertion regions; there are approximately 22 m of wigglers in the 155-m ring. The ring has a normalized horizontal emittance, including the effect on intrabeam scattering, which is less than 3×10^-6, and an emittance ratio of ε_x≈100ε_y. It is designed to damp bunches for seven vertical damping times while operating at a repetition rate of 360 Hz. Because of these requirements on the emittance and the damping per bunch, the ring operates at 1.8 GeV and is relatively large, allowing more bunches to be damped at once