Proposal for a Study of Ionization Cooling of a Low-Energy Muon Beam by LH2 and LiH Absorbers

As a step in a larger program of muon cooling R&D, we propose to study ionization cooling of 170-MeV/c muons in LH2 and LiH absorbers inside a 2-2.5 T solenoid magnet but without rf acceleration (“minicooling”). The required flux of muons is small, such that only one muon is in the apparatus at a time; the desired muon bunch will be reconstructed offline via software. This study will validate the analytic and numerical calculations of ionization cooling via measurements of multiple scattering and straggling, will demonstrate transverse cooling of a muon bunch including the predicted coupling of transverse emittance to angular momentum when inside a solenoid channel, and will use diagnostics suitable for further cooling studies. The proposed demonstration of transverse cooling via the single-particle method is a natural extension of TRIUMF E875 that is making a precision measurement of muon multiple scattering in low-Z absorbers.