Low-energy ionization cooling of ions for beta beam sources

Rubbia et al. [C. Rubbia, A. Ferrari, Y. Kadi, V. Vlachoudis, Nucl. Instr. and Meth. A 568 (2006) 475.] have recently suggested that multiturn passage of a low-energy ion beam (v/c≅0.1) through a low-Z target can be used in the production of ions useable for beta-beam sources and that ionization cooling techniques can increase the circulating beam lifetime and thus enhance that production. Some parameters in their initial discussion are somewhat optimistic, and the conditions for 3-D cooling are not completely developed. In the present paper, we reconsider some features of the scenarios and suggest some variations that may be more practical. While 3-D cooling is possible at these energies, mixing of longitudinal motion with both horizontal and vertical motion is necessary to obtain simultaneous cooling in all dimensions; we suggest lattice variations that would be needed. Direct and reverse kinematics are described and explored.