CAGE CAVITY: A LOW COST, HIGH PERFORMANCE SRF ACCELERATING STRUCTURE*

The Cage Cavity is a new cavity technology using tubes formed into the shape of a solid wall cavity then assembled into a closed volume. The theory is that the cage cavity will form a resonant cavity at RF frequencies below a critical frequency at which the cage structure behaves as a solid structure. The primary advantage of the cage cavity is cost—a cage cavity structure is estimated to be 1/20 th the cost of a solid wall structure. Several cage cavity structures have been fabricated and measured that demonstrate good RF properties. Importantly, simulations have identified a new cage cavity configuration in which an SRF cage cavity’s quality factor is >90% of a solid wall cavity. The Cage Cavity must operate in a vacuum vessel which is also an RF cavity. By choosing the cage cavity resonant frequency to be decoupled from the vessel’s higher order resonances, simulations show that the cage cavity Q can be ~95% of a solid wall SRF cavity. The Cage Cavity design, fabrication costs, and high order mode behavior have a number of advantages over solid wall cavities.