Optimizing the adiabatic buncher and phase-energy rotator for neutrino factories

In the US scenario for a Neutrino Factory presented in “A feasibility study of a neutrino source based on a muon storage ring”, N. Holtkamp (Ed.), D. Finley (Ed.), Fermilab, April 15th, 2000), a large percentage of the cost is related to an induction linac for phase-energy rotation and bunching of the muon beam collected after the production target and decay channel. A more cost-effective adiabatic buncher and phase-energy rotator has been proposed to replace the induction linac system (D. Neuffer, A. Van Ginneken, High-frequency bunching and ( φ - δ E ) rotation for a muon source, Proceedings of the 2001 Particle Accelerators Conference, Chicago, 2001, p. 2029). The new method uses consecutive RF cavities with differing frequencies. The frequencies are changed to enable bunching and phase-energy rotation. In this paper, the theoretical concept is developed and demonstrated with simulation results obtained with the map code COSY Infinity (http://cosy.pa.msu.edu). An optimization strategy is also explored.