A Tuning System for Spoke Cavities

72511-In continuous wave (CW) operations at facilities such as the Rare Isotope Accelerator (RIA), microphonically-induced vibration causes phase errors, and must be controlled by some form of fast-tuning. Spoke-loaded cavities have mechanical properties which make them more suitable for mechanical fast-tuning than the currently-used elliptical-cell structures. Based on feedback from end users, this project will design and demonstrate a compact spoke cavity tuning system. In Phase I, a prototype fast tuning actuator, based on a patented magnetostrictive material, was completed. In-house tests showed that the magnetostrictive actuator could perform reliably in a liquid helium environment, and the initial specifications for stroke, force, and operating frequency were achieved. Phase II will design and build a complete fast-response tuning system that meets more stringent specifications. In addition, a modular design will be developed for ready adaption to spoke cavities of different designs. Commercial Applications and Other Benefits as described by awardee: The new tuning system should benefit those groups who are using or planning to use spoke cavities in their facilities. The technology also should be useful in a wide range of applications that may require active vibration control. Examples include semiconductor processing equipment and many sensitive scientific instruments, such as different types of electron microscopes or interferometers.