The Mu3e experiment at the Paul Scherrer Institute in Switzerland uses one of the most intense muon beams in the world to search for the lepton-flavour violating decay of a positive muon to an electron and two positrons.
An extremely thin, fast pixel detector is combined with scintillating fibres and tiles to obtain the best possible position, momentum and time resolution. The Mainz group is building the readout system, capable of transporting up to 1 Tbit/s of data out of the experiment and identifying interesting events on-line. We are also writing the simulation and reconstruction software. Mu3e is scheduled to take first data in 2021.