Simple First Phase of an IonizationCooling

As a simple rst step in a larger program of cooling R&D, we propose to study ionization cooling in an absorber without rf acceleration (\minicooling"). The absorber and emittance diagnostics reside inside a single 2.5-T solenoid magnet placed at the end of a == quadrupole channel, either in a new beamline at FNAL, or more expediently in the existing D2 line at BNL. The ux of muons would be low, with only one muon in the apparatus at a time; the desired muon bunch would be reconstructed ooine via software. This study would validate the analytic and numerical calculations of ionization cooling via precision measurements of multiple scattering and straggling, would demonstrate transverse cooling of a bunch including the predicted minimum possible transverse cooling, would use diagnostics suitable for further cooling studies, and could serve to recommission the D2 beamline prior to transportation to a new line elsewhere. Note that an experiment to make a demonstration of \modest" transverse cooling via the single-particle method and one to make a precision measurement of multiple scattering are identical; the two results are manifestations of the same physics.