Design considerations for a second generation HOM-damped RF cavity

The first generation of strongly HOM-damped RF cavities are now being operated with beam in accelerators with good success. We briefly review these designs and consider some factors in the design of a second generation HOM damped copper RF cavity suitable for use in high current storage rings such as linear collider damping rings, light sources and high luminosity colliders. We consider the problem of broad-band coupling to the higher-order modes (HOMs) and describe how straightforward modifications to the traditional cavity shape can lead to significant simplification of the mechanical design and reduction in cost. We also consider the problem of broad-band HOM damping in a multi-cell cavity.