Muon Cooling in the MICE experiment

by Dr Chris Rogers

Muon beams of low emittance provide the basis for the intense, well-characterised neutrino beams necessary to elucidate the physics of flavour at the Neutrino Factory and to provide lepton-antilepton collisions of up to several TeV at the Muon Collider. To deliver beams with the properties necessary to meet the specifications of these facilities requires that the volume of phase space occupied by the tertiary muon beam be reduced (cooled). Existing cooling schemes cannot operate on time scales that are competitive with the muon lifetime. Ionisation cooling has been proposed as a means to achieve sufficient cooling, but it has never been demonstrated practically. In the Muon Ionisation Cooling Experiment (MICE), based at the Rutherford Appleton Laboratory (RAL), ionisation cooling will be demonstrated. MICE Step IV is currently in progress. Muons are brought onto an absorber, resulting in a reduction of momentum and hence reduction of normalised transverse emittance. The full Demonstration of Ionisation Cooling will take place in 2018. An extra magnet module and RF cavities will be installed, as in a cell of a cooling channel. This will enable the demonstration of reduction of emittance and subsequent re-acceleration, both critical components for a realistic ionisation cooling channel.