Impact of the RFD Linac Structure on Accelerator Technology

RFD linacs, which employ the same rf electric focusing as RFQ linacs, will have the same small diameter beams that we find in RFQ linacs. These small diameter beams allow higher frequency operation, which in turn, implies smaller, lighter weight, and more efficient linac structures, which in turn, means less rf power to generate, less thermal load to cool, and less surface area to evacuate. The higher frequencies also offer the possibility of higher gradient operation (shorter structures). These compact linac structures will be more transportable that their predecessors, easier to enclose in radiation shielding, and less expensive to procure, maintain and operate.

This new linac structure provides a graceful way to accelerate the small diameter, tightly bunched beams that come from RFQ linacs to higher energies. We believe that this new structure will become the structure of choice to follow RFQ linacs in many applications. The performance of the RFD is much less energy dependent than its magnetically focused counterpart and can perform well at much lower energies. Consequently, the energy of transition between RFQs and RFDs will be significantly lower; perhaps in the 0.5 to 1 MeV range.

This new structure could be as revolutionary to accelerator technology as the conventional RFQ was on its introduction to the world in 1980. This new linac structure will lead to the development of a new breed of ion linac systems for a whole host of ion beam applications. These new linac systems will enhance the reliability, reduce the cost, and reduce the complexity of these sources of radiation. Applications, which formerly were out of range for linacs, may now find that they are within the range of practical linac-based systems. This represents a significant commercial business opportunity with both domestic and foreign market potential.