Components for Quasi‐Optically‐Fed Linear Accelerators

If a high‐gradient multi‐TeV electron‐positron collider is decided to be driven with millimeter waves, the high‐intensity flow might be efficiently controlled by oversized, high‐selectivity, quasi‐optical components. Two examples are discussed in the paper. The first is an accelerating structure composed of coaxial radially‐corrugated disks, where each cell is fed individually through a sufficiently broad coupler; this structure seems attractive for maximizing the accelerating gradient while avoiding RF breakdown and surface fatigue from pulsed RF heating of metallic surfaces. The second example is a delay‐line‐distribution, pulse‐compression and wave‐flow‐focusing feeder to the structure that could include control and protection components based on use of corrugated mirrors.