Beam-based detector alignment in the MICE muon beam line

The Muon Ionization Cooling Experiment (MICE) will perform a detailed study of ionization cooling to evaluate the feasibility of the technique. To carry out this program, MICE requires all of its detectors to reconstruct space points in a globally consistent fashion. The beam-based alignment constants were found to be more accurate than the survey for the scintillating-fibre trackers lodged inside the bores of the superconducting magnets. This alignment algorithm can achieve unbiased measurements of the trackers rotation angles with a resolution of 6 mrad/$\sqrt{N}$ and of their position with a resolution of 20 mm/$\sqrt{N}$, with $N$ the number of selected tracks.