Magnetic Insulation and the Effects of External Magnetic Fields on RF Cavity Operation in Muon Accelerators

High-gradient RF cavities operating in strong external magnetic fields are required for efficient and cost-effective muon ionization cooling for neutrino factories and muon colliders. However, it has been observed that the strong external magnetic fields degrade the maximum achievable gradient of typical RF cavities. One possible explanation is that the external magnetic fields focus accelerated surface-emitted electrons within the cavity to localized regions on the cavity surface, increasing the potential for surface damage and breakdown. This project will develop numerical models that can be used to help engineers design RF cavities that can operate in external magnetic fields without the potentially adverse effects of surface damage caused by surface-emitted electron bombardment. The approach involves the simulation of both the microphysics of thermal-dependent surface emission and the macrophysical dynamics of the electrons within the cavity. Commercial Applications and other Benefits as described by the awardee The tools developed during this project should be of most direct benefit to the Neutrino Factory and Muon Collider Collaboration, aiding engineers in designing the RF cavities needed for efficient muon cooling channels. In addition, particular features of the tool should benefit a variety of other industries, including the semi-conductor industry.