A bunch stacking (emittance exchange) scheme for a muon collider

An emittance exchange scheme was studied with a simple simulation model where time-separated muon minibunches were stacked transversely through mini-bunch kicker, a solenoid delay channel, and a septum-type kicker. By stacking N mini muon bunches, we obtain the longitudinal phase space reduction of 1/N in maximum, which then be converted into the increased muon transverse phase space by a factor N in minimum due to the 6 dimensional phase space conservation. Limitations in the efficiency of the emittance exchange in this scheme was discussed. The emittance exchange is a key element to obtain the 10E-5 to 10E-6 phase space cooling in the 6 dimensional muon phase space for a mu+mu-collider