June 10, 2020
The Muon Ionization Cooling Experiment (MICE) at the Rutherford Appleton Laboratory has collected extensive data to study the ionization cooling of muons. Several million individual particle tracks have been recorded passing through a series of focusing magnets in a number of different configurations and a liquid hydrogen or lithium hydride absorber. Measurement of the tracks upstream and downstream of the absorber has shown the expected effects of 4D emittance reduction. Further studies are providing more and deeper insight.