Novel Muon Cooling Channels Using Hydrogen Refrigeration and High Temperature Superconductor

Ionization cooling, a method for shrinking the size of a muon beam, requires a low Z energy absorber, high-field magnets, and high gradient RF. We have studied the use of hydrogen systems to provide ionization energy loss for muon beam cooling, breakdown suppression for pressurized high-gradient RF cavities, and refrigeration for superconducting magnets and cold RF cavities. We report progress on the designs of cryostat and refrigeration systems for different sections of muon cooling channels to achieve safe and robust means to enable exceptionally bright muon beams. We find that engineering designs can be greatly simplified if high temperature superconductor can be used that has the capability to carry adequate current in fields above 10 T for temperatures above 33 K for the use of integrated pressurized RF cavities, or for temperatures above 16 K for designs where the RF and cooling sections are sequential.