Pressurized RF Cavities for Muon Ionization Cooling

70255 Ionization cooling, a method for shrinking the size of a particle beam, is an essential technique for future particle accelerators that use muons. In particular, future muon colliders and neutrino factories will require high voltage radio frequency (RF) cavities for ionization cooling. Unlike any previous particle accelerator, muon beams in an ionization cooling channel must be accelerated through an energy absorbing material. This project will develop very high voltage RF cavities by filling them with cold, pressurized helium or hydrogen gas, which also acts as the energy absorber, to suppress high-voltage breakdown. Phase I will build an RF test cell suitable for testing the breakdown characteristics of gases that would be used in ionization cooling applications. The test cell will allow the exploration of Paschen¿s Law, relating breakdown voltages to gas density, over a range of temperatures, pressures, external magnetic fields, and ionizing particle radiation. Commercial Applications and Other Benefits as described by the awardee: The estimated cost of the ionization-cooling component of each muon collider or neutrino factory is roughly $350 million. This technology would allow the voltage of the RF cavities used in these applications to be significantly increased, which would lead to a correspondingly shorter cooling channel and smaller cost.