Rapidly Tunable RF Cavity for Accelerators

Fast cycling synchrotrons and fixed-field alternate gradient accelerators offer an attractive solution for systems that require rapid acceleration of charged particles over a wide range of energies. The ability to rapidly tune the frequency of the accelerating cavity in devices represents a fundamental barrier to their implementation in a wide variety of applications for proton, ion and muon acceleration. An innovative rf cavity design that allows for rapid tuning of the rf cavity frequency over a wide range is being developed. This cavity will be designed using computer modeling, developed though cold testing, prototyping and testing. In Phase I the basic design concept was optimized to reduce power and heating of the tuning element leading to a new design concept. Cold testing verified the performance of the ceramic material use for tuning. Issues of mode conversion and variable tune timing were studied. In Phase II the rapidly tunable rf cavity prototype will be manufactured and tested. Testing requires the construction of an rf amplifier and a ramped high-voltage biasing scheme. Lower power testing to verify the design concept will be performed prior to full cavity production. Commercial Applications and Other Benefits: Fast cycling accelerators have a potential for wide use in proton, ion, electron and muon acceleration for basic research, industrial and medical applications. The small size and the ability to accelerate large particle intensities are attractive for proton drivers, light ion accelerators, electron based synchrotron light sources, accelerator driven subcritical nuclear reactors, and cancer therapy machines. The successful development of rapidly tunable rf cavities for these machines will significantly enhance the feasibility of these accelerators for basic research, industrial, and medical applications