Complete Muon Collider Cooling Channel Design and Simulations

Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittance required for an energy- frontier muon collider. A high-performance front end from the target to the cooling systems have been designed and simulated, and many recent advances in theory, simulation codes, and hardware development have been achieved. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. This project will develop the principles and tools to optimally match the transverse and longitudinal emittance between muon beam cooling subsystems or segments that have different characteristics. An innovation that will be exploited is the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another. To address the matching of transverse emittance between subsystems, the theory of the HCC (a system that combines helical dipoles with a solenoidal field) will be extended and exploited. The HCC theory, extended to include innovative matching elements such as bent solenoids, round-to- flat beam transformers, and the twin helix, will be used to guide simulations demonstrating that the emittances of promising subsystems can be matched to each other. Commercial Applications and Other Benefits: A muon collider is the most promising way to provide a US facility for high-energy physics at the energy frontier. As a 1.5 TeV lepton collider it would complement the LHC and at higher energies it would have greater discovery potential than the LHC, where a 5 TeV muon collider would fit on the Fermilab site. Muon cooling is an essential part of this vision, and the project in this proposal promises to demonstrate that a complete cooling channel. Each of the discrete subsystems has shown great promise, and can be integrated into an effective end-to-end design. Appropriate R & amp;D can be said to reduce by 10% the cost of large projects, like a $10B muon collider. The scope of this proposal impacts at least 1% of the muon collider project, resulting in an estimated value of this proposal to the DOE is greater than $10 M.