Design of a transverse ionization-cooling channel in solenoidal focusing field

Abstract

In this study, ionization cooling in solenoidal channels is investigated for a neutrino factory. Newly designed Super-FOFO cooling channels are considered and it is shown that the transverse beam emittance in the cooling channels is reduced by a factor of six. Design and simulation of the cooling channel are performed using the ICOOL program. We describe design concepts and engineering constraints for the cooling channels. The particle losses, cooling performance, bunch lengthening and growth of momentum spread in the cooling channels are examined. It is shown that the cooling channels provide cooling performance satisfying the so-called Palmer, Johnson and Keil (PJK) design parameters for a neutrino factory. Engineering feasibility for superconducting solenoids shows that the super-FOFO cooling channel has a lower value of B J R (magnetic field B at coils x current density J x stress R on the conductor) than several cooling channels that have been designed for a neutrino factory. The simulation result for transverse cooling is also compared with that obtained using an analytical formula. It is shown that the numerical result agrees well with that of the analytical formula.